#include<bits/stdc++.h>
using namespace std;
int u,v,n,m,d[10001],b[10001],tot,ans;
vector<int>a[10001];
queue<int>q;
int main(){
    cin>>n>>m;
    while(m--){
        cin>>u>>v;
        a[v].push_back(u);
        ++d[u];
    }
    for(int i = 1;i<=n;i++){
        if(d[i]==0){
            q.push(i);
            b[i]=100;
        } 
    }
    while(!q.empty()){
        ++tot;
        v=q.front();
        q.pop();
        ans+=b[v];
        for(int i = 0;i<int(a[v].size());i++){
            u=a[v][i];
            b[a[v][i]]=max(b[v]+1,b[u]);
            if((--d[u])==0)q.push(u);
        }
    }
    if(tot<n) cout<<"Poor Xed"<<endl;
    else cout<<ans<<endl;
    return 0;
}