# pragma GCC optimize("Ofast")
# pragma GCC target("avx,avx2,fma")
# pragma GCC optimization ("unroll-loops")
# include <bits/stdc++.h>
std::pair<int,int> DR[] = {{-1,0},{0,1},{1,0},{0,-1},{-1,1},{-1,-1},{1,1},{1,-1}};
# define ll long long
# define clock (clock() * 1000.0 / CLOCKS_PER_SEC)
# define rc(s) return cout << s,0
# define rcg(s) cout << s;exit(0)
# define _ ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
# define db(x) cerr << #x << " = " << x << '\n'
# define pb push_back
# define mp make_pair
# define all(s) s.begin(),s.end()
# define sz(x) (int)((x).size())
//# define int ll
using namespace std;
int gcd(int a, int b)
{
    if(b) return gcd(b,a%b);
    return a;
}mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int n,m,e,a,b;
vector<int>vec[10005];
int p[10005],viz[10005];
int ans;

bool f(int nod)
{
	for(auto it : vec[nod])
	{
		if(!viz[it])
		{
			viz[it] = 1;
			if(!p[it] || f(p[it]))
			{
				p[it] = nod;
				return 1;
			}
		}
	}
	return 0;
}

int32_t main(){_
    freopen("cuplaj.in","r",stdin);
    freopen("cuplaj.out","w",stdout);
	cin >> n >> m >> e;
	for(int i = 1;i <= e;i++)
	{
		cin >> a >> b;
		vec[a].pb(b);
	}
	for(int i = 1;i <= n;i++)
	{
		memset(viz,0,sizeof(viz));
		if(f(i)) ans++;
	}
	cout << ans << '\n';
	for(int i = 1;i <= m;i++)
	{
		if(p[i]) cout << p[i] << ' ' << i << '\n';
	}
}