#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstdlib>
#include <vector>
#include <set>
#include <map>
#include <cassert>
#include <ctime>
#include <cmath>
#include <string>
#include <cstring>
#include <queue>
using namespace std;

#define f first
#define s second
#define pb push_back
#define vi vector<int>
#define all(v) (v).begin(), (v).end()
#define sz(v) (int)(v).size()
#define f0(a) memset(a, 0, sizeof(a))
#define ll long long
#define pii pair<int, int>
#define mp make_pair
const int maxn = (int)1e5;
int n, m;
vi g[maxn], gi[maxn];
bool used[maxn][2];
int ans;
void Dfs(int v, int d) {

    if (used[v][d]) return;
    used[v][d] = true;

    if (d == 0) {
        for (int u : gi[v]) {
            Dfs(u, 0);
        }
    }

    for (int u : g[v])
        Dfs(u, 1);
}

int main() {
    scanf("%d%d", &n, &m);
    for (int i = 0; i < m; ++i) {
        int u, v;
        scanf("%d%d", &u, &v); --u; --v;
        g[u].pb(v);
        gi[v].pb(u);
    }

    for (int i = 0; i < n; ++i) {

        for (int j = 0; j < n; ++j)
            used[j][0] = used[j][1] = false;

        Dfs(i, 0);
        for (int j = 0; j < n; ++j)
            if (used[j][0] || used[j][1]) {
                ++ans;
            }
    }
    cout << ans << endl;
    return 0;
}