1 #include "bits/stdc++.h"
 2 using namespace std;
 3 typedef long long LL;
 4 const int MAX=505;
 5 int n,m;
 6 int a[MAX][MAX];
 7 int degree[MAX];
 8 priority_queue <int , vector<int>, greater<int> > q;
 9 int main(){
10     freopen ("sort.in","r",stdin);
11     freopen ("sort.out","w",stdout);
12     int i,j;
13     int u,v,x;
14     while (~scanf("%d%d",&n,&m)){
15     while (q.size()) q.pop();
16     memset(a,0,sizeof(a));
17     memset(degree,0,sizeof(degree));
18     for (i=1;i<=m;i++){
19         scanf("%d%d",&u,&v);
20         if (a[u][v]==0){
21             a[u][v]=1;
22             degree[v]++;
23         }
24     }
25     for (i=1;i<=n;i++){
26         if (degree[i]==0){
27             q.push(i);
28         }
29     }
30     x=0;
31     while (q.size()){
32         x++;
33         u=q.top();
34         q.pop();
35         if (x==n)
36             printf("%d\n",u);
37         else
38             printf("%d ",u);
39         for (i=1;i<=n;i++){
40             if (a[u][i]){
41                 degree[i]--;
42                 if (degree[i]==0){
43                     q.push(i);
44                 }
45             }
46         }
47     }
48     }
49     return 0;
50 }