#include <bits/stdc++.h>
using namespace std;
const int N = 10010, M = 30010;
int din[N];  //记录每个节点入度
int dist[N]; //记录每个节点距离起点的最小值
int cnt[N];  // cnt[i]记录以节点i为终点的路径的边数
bool st[N];
queue<int> q;
int n, m;
//邻接表
int e[M], h[N], idx, w[M], ne[M];
void add(int a, int b, int c) {
    e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx++;
}

bool spfa() {
    memset(dist, -0x3f, sizeof dist);
    q.push(0);
    st[0] = true;
    dist[0] = 0;

    while (q.size()) {
        int u = q.front();
        q.pop();
        st[u] = false;

        for (int i = h[u]; ~i; i = ne[i]) {
            int j = e[i];
            if (dist[j] < dist[u] + w[i]) {
                dist[j] = dist[u] + w[i]; //最长路,判正环
                cnt[j] = cnt[u] + 1;
                if (cnt[j] > n + 1) return false;
                if (!st[j]) {
                    q.push(j);
                    st[j] = true;
                }
            }
        }
    }
    return true;
}

int main() {
    memset(h, -1, sizeof h);
    scanf("%d %d", &n, &m);
    while (m--) {
        int a, b;
        scanf("%d %d", &a, &b);
        add(b, a, 1);
    }

    //超级源点0号点
    for (int i = 1; i <= n; i++) add(0, i, 100);

    if (spfa()) {
        int res = 0;
        for (int i = 1; i <= n; i++) res += dist[i];
        printf("%d\n", res);
    } else
        puts("Poor Xed");
    return 0;
}