o22_oct_topo

#include <bits/stdc++.h>

using namespace std;
const int N = 1e5 + 10;
vector <int> g[N];
int color[N], indeg[N];
bool vs[N];

bool cycle(int u){
    if(color[u] == 1)
        return true;
    if(color[u] == 2)
        return false;
    color[u] = 1;
    for(auto v: g[u]){
        if(cycle(v))
            return true;
    }
    color[u] = 2;
    return false;
}

int main(){

    int n, m;
    scanf("%d %d", &n, &m);

    for(int i=1;i<=m;i++){
        int u, v;
        scanf("%d %d", &u, &v);
        g[u].push_back(v);
        indeg[v] ++;
    }

    if(cycle(1)){
        printf("no");
        return 0;
    }

    queue <int> q;
    for(int u=1;u<=n;u++){
        if(indeg[u] == 0)
            q.push(u);
    }

    while(!q.empty()){
        int u = q.front();
        q.pop();
        printf("%d\n", u);
        for(auto v: g[u]){
            indeg[v] --;
            if(indeg[v] == 0 and !vs[v])
                q.push(v);
        }
    }

    return 0;
}