/*input
5 7 2 5
3 1 7 -1
1 4 3 0
3 4 3 -4
1 5 7 0
4 5 1 1
2 5 8 -3
2 3 4 -3
*/
#include <bits/stdc++.h>
using namespace std;
#define sp ' '
#define endl '\n'
#define fi first
#define se second
#define mp make_pair
#define __builtin_popcount __builtin_popcountll
#define int long long
#define bit(x,y) ((x>>y)&1LL)
#define loop(i,l,r) for(int i=(int)l; i<=(int)r; i++)
#define rloop(i,l,r) for(int i=(int)l; i>=(int)r; i--)

template <class T1, class T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &a) {
	return os << '(' << a.first << ", " << a.second << ')';
}
template <class T>
ostream &operator<<(ostream &os, const vector<T> &a) {
	os << '[';
	for (unsigned int i = 0; i < a.size(); i++)
		os << a[i] << (i < a.size() - 1 ? ", " : "");
	os << ']';
	return os;
}

// Push-Relabel implementation of the cost-scaling algorithm
// Runs in O( <max_flow> * log(V * max_edge_cost)) = O( V^2 E * log(V * C))
// Really fast in practice, like O(V * E), so 3e4 edges are fine.
// Operates on integers, costs are multiplied by N!!

// This version uses the look-ahead heuristic as described in
// "An efficient implementation of a scaling minimum-cost Flow algorithm"
// by A.V. Goldberg (1992)

template<typename flow_t = int, typename cost_t = int>
struct mcSFlow{
    struct Edge{
        cost_t c;
        flow_t f;
        int to, rev;
        Edge(int _to, cost_t _c, flow_t _f, int _rev):c(_c), f(_f), to(_to), rev(_rev){}
    };
    static constexpr cost_t INFCOST = numeric_limits<cost_t>::max()/2;
    cost_t eps;
    int N, S, T;
    vector<vector<Edge> > G;
    vector<unsigned int> isq, cur;
    vector<flow_t> ex;
    vector<cost_t> h;
    mcSFlow(int _N, int _S, int _T):eps(0), N(_N), S(_S), T(_T), G(_N){}
    void add_edge(int a, int b, cost_t cost, flow_t cap){
		assert(cap>=0);
        assert(a>=0&&a<N&&b>=0&&b<N);
        if(a==b){assert(cost>=0); return;}
        cost*=N;
        eps = max(eps, abs(cost));
        G[a].emplace_back(b, cost, cap, G[b].size());
        G[b].emplace_back(a, -cost, 0, G[a].size()-1);
    }
    void add_flow(Edge& e, flow_t f) {
        Edge &back = G[e.to][e.rev];
        if (!ex[e.to] && f)
            hs[h[e.to]].push_back(e.to);
        e.f -= f; ex[e.to] += f;
        back.f += f; ex[back.to] -= f;
    }
    vector<vector<int> > hs;
    vector<int> co;
    flow_t max_flow() {
        ex.assign(N, 0);
        h.assign(N, 0); hs.resize(2*N);
        co.assign(2*N, 0); cur.assign(N, 0);
        h[S] = N;
        ex[T] = 1;
        co[0] = N-1;
        for(auto &e:G[S]) add_flow(e, e.f);
        if(hs[0].size())
        for (int hi = 0;hi>=0;) {
            int u = hs[hi].back();
            hs[hi].pop_back();
            while (ex[u] > 0) { // discharge u
                if (cur[u] == G[u].size()) {
                    h[u] = 1e9;
                    for(unsigned int i=0;i<G[u].size();++i){
                        auto &e = G[u][i];
                        if (e.f && h[u] > h[e.to]+1){
                            h[u] = h[e.to]+1, cur[u] = i;
                        }
                    }
                    if (++co[h[u]], !--co[hi] && hi < N)
                        for(int i=0;i<N;++i)
                            if (hi < h[i] && h[i] < N){
                                --co[h[i]];
                                h[i] = N + 1;
                            }
                    hi = h[u];
                } else if (G[u][cur[u]].f && h[u] == h[G[u][cur[u]].to]+1)
                    add_flow(G[u][cur[u]], min(ex[u], G[u][cur[u]].f));
                else ++cur[u];
			}
            while (hi>=0 && hs[hi].empty()) --hi;
        }
        return -ex[S];
    }
    void push(Edge &e, flow_t amt){
        if(e.f < amt) amt=e.f;
        e.f-=amt; ex[e.to]+=amt;
        G[e.to][e.rev].f+=amt; ex[G[e.to][e.rev].to]-=amt;
    }
    void relabel(int vertex){
        cost_t newHeight = -INFCOST;
        for(unsigned int i=0;i<G[vertex].size();++i){
            Edge const&e = G[vertex][i];
            if(e.f && newHeight < h[e.to]-e.c){
                newHeight = h[e.to] - e.c;
                cur[vertex] = i;
            }
        }
        h[vertex] = newHeight - eps;
    }
    static constexpr int scale=2;
    pair<flow_t, cost_t> minCostMaxFlow(){
        cost_t retCost = 0;
        for(int i=0;i<N;++i)
            for(Edge &e:G[i])
                retCost += e.c*(e.f);
        //find max-flow
        flow_t retFlow = max_flow();
        h.assign(N, 0); ex.assign(N, 0);
        isq.assign(N, 0); cur.assign(N,0);
        queue<int> q;
        for(;eps;eps>>=scale){
            //refine
            fill(cur.begin(), cur.end(), 0);
            for(int i=0;i<N;++i)
                for(auto &e:G[i])
                    if(h[i] + e.c - h[e.to] < 0 && e.f) push(e, e.f);
            for(int i=0;i<N;++i){
                if(ex[i]>0){
                    q.push(i);
                    isq[i]=1;
                }
            }
            // make flow feasible
            while(!q.empty()){
                int u=q.front();q.pop();
                isq[u]=0;
                while(ex[u]>0){
                    if(cur[u] == G[u].size())
                        relabel(u);
                    for(unsigned int &i=cur[u], max_i = G[u].size();i<max_i;++i){
                        Edge &e=G[u][i];
                        if(h[u] + e.c - h[e.to] < 0){
                            push(e, ex[u]);
                            if(ex[e.to]>0 && isq[e.to]==0){
                                q.push(e.to);
                                isq[e.to]=1;
                            }
                            if(ex[u]==0) break;
                        }
                    }
                }
            }
            if(eps>1 && eps>>scale==0){
                eps = 1<<scale;
            }
        }
        for(int i=0;i<N;++i){
            for(Edge &e:G[i]){
                retCost -= e.c*(e.f);
            }
        }
        return make_pair(retFlow, retCost/2/N);
    }
    flow_t getFlow(Edge const &e){
        return G[e.to][e.rev].f;
    }
};


signed main() {
#ifndef UncleGrandpa
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#endif
	freopen("fmcm.in", "r", stdin);
	freopen("fmcm.out", "w", stdout);
	int n, m, S, T;
	cin >> n >> m >> S >> T;
	mcSFlow<int, int> flow(n + 5, S, T);
	while (m--) {
		int u, v, cap, cost;
		cin >> u >> v >> cap >> cost;
		flow.add_edge(u, v, cost, cap);
	}
	cout << flow.minCostMaxFlow().se << endl;
}