#include <bits/stdc++.h>

using namespace std;
ifstream f("sortaret.in");
ofstream g("sortaret.out");
const int N = 50010;
int n,m,x,y,lo,hi,gr[N],sol[N];
vector<int> v[N];
queue<int> q;
int main()
{
    f>>n>>m;
    for(; m; m--)
    {
        f>>x>>y;
        v[x].push_back(y);
        gr[y]++;
    }
    for(int i=1;i<=n;i++)
        if(!gr[i])
            sol[++hi]=i;
    lo=1;
    for(;hi<n;lo++)
    {
        x=sol[lo];
        for(auto vec:v[x])
        {
            gr[vec]--;
            if(!gr[vec])
                sol[++hi]=vec;
        }
    }
    return 0;
}