1 #include<bits/stdc++.h>
2 using namespace std;
3 const int N=160,M=6010;
4 int n,m,link[N<<1];
5 vector<int>point[N<<1];
6 bool used[N<<1],start[N];
7 bool find(int k){
8 for(int i=0;i<point[k].size();i++)if(!used[point[k][i]]){
9 used[point[k][i]]=1;
10 if(!link[point[k][i]]||find(link[point[k][i]])){
11 link[point[k][i]]=k;
12 return 1;
13 }
14 }
15 return 0;
16 }
17 bool vis[N];
18 int main(){
19 int t1,t2,ans=0;
20 scanf("%d%d",&n,&m);
21 for(int i=1;i<=m;i++){
22 scanf("%d%d",&t1,&t2);
23 point[t2].push_back(t1+n);
24 }
25 for(int i=1;i<=n;i++){
26 memset(used,0,sizeof(used));
27 if(find(i)) ans++;
28 }
29 ans=n-ans;
30 for(int i=1;i<=n;i++){
31 if(vis[i]) continue;
32 vis[i]=1;
33 t1=link[i+n];
34 while(t1){
35 vis[t1]=start[t1]=1;
36 t1=link[t1+n];
37 }
38 }
39 for(int i=1;i<=n;i++)if(!start[i]){
40 t1=i;
41 while(t1){
42 printf("%d ",t1);
43 t1=link[t1+n];
44 }
45 printf("\n");
46 }
47 printf("%d",ans);
48 }
