#include<bits/stdc++.h>
#include<atcoder/scc>
using namespace std;

int main(){
  int n,m,K;
  cin>>n>>m>>K;
  vector<vector<int>> g(n);
  atcoder::scc_graph g2(n);
  for (int i=0;i<m;i++){
    int u,v;
    cin>>u>>v;
    u--;v--;
    g[u].push_back(v);
    g2.add_edge(u,v);
  }
  auto scc=g2.scc();
  int k=scc.size();
  vector<int> group(n);
  for (int i=0;i<k;i++) for (int v:scc[i]) group[v]=i;
  for (int i=0;i<k-1;i++){
    bool f=false;
    for (int v:scc[i]){
      for (int u:g[v]){
        if (group[u]==i+1) f=true;
      }
    }
    if (!f){
      cout<<"No\n";
      return 0;
    }
  }
  vector<int> col(n,-1);
  vector<bool> bip(k,true);
  auto dfs=[&](auto dfs,int v)-> void {
    if (col[v]==-1) col[v]=0;
    for (int u:g[v]){
      if (group[v]!=group[u]) continue;
      if (col[u]==-1){
        col[u]=col[v]^1;
        dfs(dfs,u);
      }
      if (col[u]!=col[v]^1) bip[group[v]]=false;
    }
  };
  for (int i=0;i<n;i++) dfs(dfs,i);
  if (count(bip.begin(),bip.end(),true)) cout<<"No\n";
  else cout<<"Yes\n";
}