#include <bits/stdc++.h>
using namespace std;
ifstream fi("ctc.in");
ofstream fo("ctc.out");

const int NMAX = 1e5 + 5;

vector <int> G[NMAX], H[NMAX];
vector <int> p[NMAX];
int comp[NMAX];
int n, m;



int main()
{
    fi >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        int u, v;
        fi >> u >> v;
        G[u].push_back(v);
        H[v].push_back(u);
    }

    for (int i = 1; i <= n; i++)
        if (!comp[i])
        {
            nr++;
            dfs(i, G);
            dfs(i, H);
        }

    fo << nr << "\n";
    for (int i = 1; i <= nr; i++)
        for (auto x: )

    return 0;
}