#include <fstream>
#include <vector>
#include <queue>

using namespace std;

ifstream f("sortaret.in");
ofstream g("sortaret.out");

int n,m,x,y;
vector<int> inDegree;
queue<int> q;

void topSort(const vector<vector<int>>& adj){
    
    while(!q.empty()){
        int nod = q.front();
        q.pop();
        
        g << nod << " ";

        for(auto& neigh: adj[nod]){
            inDegree[neigh]--;

            if(inDegree[neigh] == 0){
                q.push(neigh);
            }
        }
    }
}

int main(){

    f >> n >> m;
    inDegree.resize(n+1, 0);
    vector<vector<int>> adj(n+1);

    for(int i=1; i<=m; i++){
        f >> x >> y;
        adj[x].push_back(y);
        inDegree[y]++;
    }
    for(int i=1; i<=n; i++){
        if(inDegree[i] == 0){
            q.push(i);
        }
    }
    if(q.empty())
        g << -1;

    topSort(adj);

    return 0;
}