1 //2018年5月27日 11:26:43
 2 #include <iostream>
 3 #include <cstdio>
 4 #include <cstring>
 5 #include <queue>
 6 using namespace std;
 7 
 8 const int N = 500;
 9 const int M = 1001;
10 
11 int n, m;
12 int inDeg[N];
13 
14 int fir[N], cnt;
15 struct Edge{
16     int nxt;
17     int to;
18 }E[M];
19 
20 void addEdge(int x, int y){
21     E[++cnt].to = y;
22     E[cnt].nxt = fir[x];
23     fir[x] = cnt;
24 }
25 
26 void Topsort(){
27     priority_queue<int, vector<int>, greater<int> > q;
28     for(int i=1; i<=n; i++)
29         if(inDeg[i] == 0)
30             q.push(i);
31     int flag = 0;
32     while(!q.empty()){
33         int v = q.top();
34         q.pop();
35         if(flag) printf(" ");
36         printf("%d", v);
37         flag = 1;
38         for(int i=fir[v]; i; i=E[i].nxt){
39             inDeg[E[i].to]--;
40             if(!inDeg[E[i].to]) q.push(E[i].to);
41         }
42     }
43     printf("\n"); 
44 }
45 
46 int main(){
47     while(scanf("%d%d", &n, &m) != EOF){
48         memset(E, 0, sizeof(E)); cnt = 0;
49         memset(inDeg, 0, sizeof(inDeg));
50         memset(fir, 0, sizeof(fir));
51         for(int i=1; i<=m; i++){
52             int x, y;
53             scanf("%d%d", &x, &y);
54             addEdge(x, y);
55             inDeg[y]++;
56         }
57         Topsort();
58     }
59         
60     return 0;
61 }