#include 
     
      #include 
      
       using namespace std;const int MAX_N=100;const int MAX_M=10000;struct edge{    int v,next;    int len;}E[MAX_M];int p[MAX_N],eid;void init(){    memset(p,-1,sizeof(p));    eid=0;}void insert(int u,int v){    E[eid].v=v;    E[eid].next=p[u];    p[u]=eid++;}void tarjan(int u){    dfn[u]=low[u]=++idx;    s[top++]=u;    in_stack[u]=true;    for(int i=p[u];i+1;i=E[i].next){        int v=E[i].v;        if(!dfn[v]){            tarjan(v);            low[u]=min(low[u],low[v]);        }else if(in_stack[v]){            low[u]=min(low[u],dfn[v]);        }    }    if(dfn[u]==low[u]){        ++scc;        do{            belong[s[--top]]=scc;            in_stack[s[top]]=false;        }while(s[top]!=u);    }}int main() {    int n,m;    init();    cin>>n>>m;    for(int i=0;i
       
        >u>>v;        insert(u,v);    }    memset(dfn,0,sizeof(dfn));    idx=0;    for(int i=1;i<=n;++i){        if(!dfn[i]){            tarjan(i);        }    }    for(int i=1;i<=scc;i++){        cout<<"block "<
        <<": ";        for(int j=1;j<=n;j++){           if(belong[j]==i){              cout<
         
          <<" ";           }        }        cout<