#include<fstream>
#include<vector>
#include<queue>
#define vec G[nod][i]
#define NMAX 355
#define DIJKSTRA_TYPE pair<int,int> 
using namespace std;
int n,source,destination,DIST[NMAX],FLUX[NMAX][NMAX],CAPACITY[NMAX][NMAX],COST[NMAX][NMAX],INF=(1<<30),VOLMIN,sol,D,TT[NMAX];
vector<int> G[NMAX];
priority_queue<DIJKSTRA_TYPE, vector<DIJKSTRA_TYPE>, greater<DIJKSTRA_TYPE> > HEAP;
inline void init()
{
	for(int i=1;i<=n;i++)
		if(DIST[i]<INF)
			DIST[i]=INF;
}
char buffer[1000000],*p=buffer;
inline void transform(int &s)
{
	short minus=1;
	s=0;
	if(*p=='-')
	{
		minus=-1;
		p++;
	}
	for(;*p>='0' && *p<='9';p++)
		s=s*10+(*p-'0');
	s*=minus;
	p++;
}
inline void parse(int &a,int &b,int &c,int &d)
{
	transform(a);
	transform(b);
	transform(c);
	transform(d);
}
void read()
{
	ifstream fin("fmcm.in");
	fin.read(buffer,1000000);
	fin.close();
	int m,z,c;
	parse(n,m,source,destination);
	int x,y;
	while(m--)
	{
		parse(x,y,z,c);
		G[x].push_back(y);
		G[y].push_back(x);
		CAPACITY[x][y]=z;
		COST[x][y]=c;
		COST[y][x]=-c;
	}
}
void print()
{
	ofstream fout("fmcm.out");
	fout<<sol<<'\n';
	fout.close();
}
inline void flux_update()
{
	int i;
	VOLMIN=INF;
	for(i=destination;i!=source;i=TT[i])
		VOLMIN=min(VOLMIN,CAPACITY[TT[i]][i]-FLUX[TT[i]][i]);
	for(i=destination;i!=source;i=TT[i])
	{
		FLUX[TT[i]][i]+=VOLMIN;
		FLUX[i][TT[i]]-=VOLMIN;
	}
	D+=DIST[destination];
	sol+=(VOLMIN*D);
}
void DIJKSTRA_INIT()
{
	for(int nod=1;nod<=n;nod++)
		if(DIST[nod]!=INF)
			for(size_t i=0;i<G[nod].size();i++)
				if(DIST[vec]!=INF)
					COST[nod][vec]+=(DIST[nod]-DIST[vec]);
	init();
}
inline bool dijkstra()
{
	DIJKSTRA_INIT();
	DIST[source]=0;
	HEAP.push(make_pair(0,source));
	int nod,cst,cost;
	while(!HEAP.empty())
	{
		nod=HEAP.top().second;
		cst=HEAP.top().first;
		HEAP.pop();
		if(DIST[nod]!=cst)
			continue;
		for(size_t i=0;i<G[nod].size();i++)
			if(CAPACITY[nod][vec]>FLUX[nod][vec])
			{
				cost=COST[nod][vec];
				if(cst+cost<DIST[vec])
				{
					DIST[vec]=cst+cost;
					TT[vec]=nod;
					HEAP.push(make_pair(DIST[vec],vec));
				}
			}
	}
	return (DIST[destination]<INF);
}
int main()
{
	read();
	while(dijkstra())
		flux_update();
	print();
	return 0;
}