#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 1ll << 60;
#define REP(i, n) for(ll i =0; i < ll(n); i++)
template <class T> using V = vector<T>;
template <class A, class B>
bool chmax(A& a, B b) { return a<b && (a=b, true); }
template <class A, class B>
bool chmin(A& a, B b) { return b<a && (a=b, true); }

void testcase() {
  int n, m, k; cin >> n >> m >> k;
  V<V<int>> g(n);
  REP(i, m) {
    int u, v; cin >> u >> v; u--; v--;
    g[u].push_back(v);
  }
  V<V<int>> seen(2, V<int>(n));
  stack<pair<int, int>> stk;
  seen[0][0] = 1;
  stk.emplace(0, 0);
  while(!stk.empty()) {
    auto [d, u] = stk.top(); stk.pop();
    for(int v : g[u]) {
      if(seen[d^1][v]) continue;
      seen[d^1][v] = 1;
      stk.emplace(d^1, v);
    }
  }
  REP(i, 2) REP(j, n) {
    if(!seen[i][j]) {
      cout << "No\n";
      return;
    }
  }
  cout << "Yes\n";
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  testcase();
}