https://www.luogu.com.cn/problem/P3386

#include <bits/stdc++.h>
using namespace std;
const int M = 2e5 + 5;
int match[M], vis[M];
vector<int> f[M];

bool dfs(int now)
{
    for (auto x : f[now])
        if (!vis[x])
        {
            vis[x] = 1;
            if (!match[x] || dfs(match[x]))
            {
                match[x] = now;
                return 1;
            }
        }
    return 0;
}

void solve()
{
    int n, m, t;
    cin >> n >> m >> t;
    while (t--)
    {
        int x, y;
        cin >> x >> y;
        f[x].push_back(y);
    }
    int ans = 0;
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= m; ++j)
            vis[j] = 0;
        if (dfs(i))
            ans++;
    }
    cout << ans;
}

signed main()
{
    ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    int t = 1;
    // cin>>t;
    while (t--)
        solve();
    return 0;
}