#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define ull unsigned ll
#define vec vector
#define flist forward_list
#define um unordered_map
#define us unordered_set
#define prioq priority_queue
#define all(x) x.begin(), x.end()
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define mp make_pair
#define mt make_tuple
#define ld long double
#define pll pair<ll, ll>

#define LL_MAX LLONG_MAX
#define LL_MIN LLONG_MIN
#define ULL_MAX ULLONG_MAX
#define ULL_MIN 0
#define LD_MAX LDBL_MAX
#define LD_MIN LDBL_MIN

#define nl '\n'

#define vv(type, name, n, ...) vector<vector<type>> name(n, vector<type>(__VA_ARGS__))
#define vvv(type, name, n, m, ...)                                                                                     \
    vector<vector<vector<type>>> name(n, vector<vector<type>>(m, vector<type>(__VA_ARGS__)))

// https://trap.jp/post/1224/
#define rep1(n) for(ll i=0; i<(ll)(n); ++i)
#define rep2(i,n) for(ll i=0; i<(ll)(n); ++i)
#define rep3(i,a,b) for(ll i=(ll)(a); i<(ll)(b); ++i)
#define rep4(i,a,b,c) for(ll i=(ll)(a); i<(ll)(b); i+=(c))
#define cut4(a,b,c,d,e,...) e
#define rep(...) cut4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
#define rep1e(n) for(ll i=1; i<=(ll)(n); ++i)
#define rep2e(i,n) for(ll i=1; i<=(ll)(n); ++i)
#define rep3e(i,a,b) for(ll i=(ll)(a); i<=(ll)(b); ++i)
#define rep4e(i,a,b,c) for(ll i=(ll)(a); i<=(ll)(b); i+=(c))
#define repe(...) cut4(__VA_ARGS__,rep4e,rep3e,rep2e,rep1e)(__VA_ARGS__)
#define per1(n) for(ll i=((ll)n)-1; i>=0; --i)
#define per2(i,n) for(ll i=((ll)n)-1; i>=0; --i)
#define per3(i,a,b) for(ll i=((ll)a)-1; i>=(ll)(b); --i)
#define per4(i,a,b,c) for(ll i=((ll)a)-1; i>=(ll)(b); i-=(c))
#define per(...) cut4(__VA_ARGS__,per4,per3,per2,per1)(__VA_ARGS__)
#define per1e(n) for(ll i=((ll)n); i>=1; --i)
#define per2e(i,n) for(ll i=((ll)n); i>=1; --i)
#define per3e(i,a,b) for(ll i=((ll)a); i>=(ll)(b); --i)
#define per4e(i,a,b,c) for(ll i=((ll)a); i>=(ll)(b); i-=(c))
#define pere(...) cut4(__VA_ARGS__,per4e,per3e,per2e,per1e)(__VA_ARGS__)
#define rep_subset(i,s) for(ll i=(s); i>=0; i=(i==0?-1:(i-1)&(s)))
// #define forit(v) for (auto it = v.begin(); it != v.end(); it++)
// #define forit2(it, v) for (auto it = v.begin(); it != v.end(); it++)
// #define forrit(v) for (auto it = v.rbegin(); it != v.rend(); it++)
// #define forrit2(it, v) for (auto it = v.rbegin(); it != v.rend(); it++)

// #ifdef i_am_noob
#define bug(...) cerr << "#" << __LINE__ << ' ' << #__VA_ARGS__ << "- ", _do(__VA_ARGS__)
template<typename T> void _do(vector<vector<T>> x){cerr << "\n"; for(auto i: x) {for(auto j : i) {cerr << j << ' ';} cerr << "\n";}}
template<typename T> void _do(vector<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(set<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(unordered_set<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(T && x) {cerr << x << endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr << x << ", "; _do(y...);}
// #else
// #define bug(...) 777771449
// #endif

const ll MOD = 1e9 + 7;

const string FILENAME = "cuplaj";
ifstream fin(FILENAME + ".in");
ofstream fout(FILENAME + ".out");

#define cin fin
#define cout fout

void solve();

struct edge
{
	ll begin, end, res;
};

ll n, m, k;
vec<edge> edges;
vec<flist<ll>> adj;

ll dfs(ll node, ll flow, vec<flist<ll>::iterator>& ptr, vec<ll>& level)
{
	if(node == n + m + 1) return flow;
	
	for(; ptr[node] != adj[node].end(); ptr[node]++)
	{
		ll v = edges[*ptr[node]].end, *rp = &edges[*ptr[node]].res, res = *rp;
		
		if(v == node)
		{
			v = edges[*ptr[node]].begin;
			res = !res;
		}
		
		if(level[v] != level[node] + 1 || res == 0) continue;
		
		ll pushed = dfs(v, 1, ptr, level);
		if(pushed == 0) continue;
		
		*rp = !(*rp);
		
		return pushed;
	}
	
	return 0;
}

int main()
{
	cin >> n >> m >> k;
	
	edges.resize(n + m + k);
	adj.resize(n + m + 2);
	
	rep(k)
	{
		ll a, b;
		
		cin >> a >> b;
		
		b += n;
		
		edges[i].begin = a;
		edges[i].end = b;
		edges[i].res = 1;
		
		adj[a].pf(i);
		adj[b].pf(i);
	}
	
	repe(n)
	{
		edges[k + i - 1].begin = 0;
		edges[k + i - 1].end = i;
		edges[k + i - 1].res = 1;
		
		adj[0].pf(k + i - 1);
		adj[i].pf(k + i - 1);
	}
	
	repe(m)
	{
		edges[n + k + i - 1].begin = i + n;
		edges[n + k + i - 1].end = n + m + 1;
		edges[n + k + i - 1].res = 1;
		
		adj[i + n].pf(n + k + i - 1);
		adj[n + m + 1].pf(n + k + i - 1);
	}
	
	ll maxFlow = 0;
	vec<ll> level(n + m + 2);
	vec<flist<ll>::iterator> ptr(n + m + 2);
	
	while(true)
	{
		rep(level.size()) level[i] = -1;
		
		queue<ll> nn;
		ll node;
		
		level[0] = 0;
		nn.push(0);
		
		while(!nn.empty())
		{
			node = nn.front();
			nn.pop();
			
			for(auto id : adj[node])
			{
				ll v = edges[id].end, res = edges[id].res;
				
				if(node == v)
				{
					v = edges[id].begin;
					res = !res;
				}
				
				if(level[v] == -1 && res)
				{
					level[v] = level[node] + 1;
					nn.push(v);
				}
			}
		}
		
		if(level[n + m + 1] == -1) break;
		
		rep(ptr.size()) ptr[i] = adj[i].begin();
		ll pushed = dfs(0, INT_MAX, ptr, level);
		
		while(pushed)
		{
			maxFlow += pushed;
			pushed = dfs(0, INT_MAX, ptr, level);
		}
	}
	
	cout << maxFlow << nl;
	
	for(auto e : edges)
	{
		if(1 <= e.begin && e.begin <= n && n + 1 <= e.end && e.end <= n + m && e.res == 0)
		{
			cout << e.begin << ' ' << e.end - n << nl;
		}
	}
	
    return 0;
}

void solve()
{
	
}