#include using namespace std; using ll = long long; using uns= unsigned long long; #define rep(i,a,b) for(ll i = (a); i < (b); i++) int main() { int N,M; cin>>N>>M; vector> data(N+1); rep(i,0,M){ int a,b; cin>>a>>b; vector seen(N+1,0); queue que; seen.at(b)=1; que.push(b); int ok=1; while(!que.empty()){ for(int t:data.at(que.front())){ if(seen.at(t)==0){ que.push(t); seen.at(t)=1; } if(t==a){ ok=0; } } que.pop(); } if(ok){ cout<<0<