#include <iostream>
#include <numeric>
#include <queue>
#include <vector>

int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);

  int N, M, K;
  std::cin >> N >> M >> K;
  std::vector<std::vector<int>> adj(N + 1), radj(N + 1);
  for (int i = 0; i < M; ++i) {
    int u, v;
    std::cin >> u >> v;
    adj[u].push_back(v);
    radj[v].push_back(u);
  }

  std::vector<char> fwd(N + 1, 0), rev(N + 1, 0);
  {
    std::queue<int> q;
    q.push(1);
    fwd[1] = 1;
    while (!q.empty()) {
      int u = q.front();
      q.pop();
      for (int v : adj[u]) {
        if (!fwd[v]) {
          fwd[v] = 1;
          q.push(v);
        }
      }
    }
  }
  {
    std::queue<int> q;
    q.push(1);
    rev[1] = 1;
    while (!q.empty()) {
      int u = q.front();
      q.pop();
      for (int v : radj[u]) {
        if (!rev[v]) {
          rev[v] = 1;
          q.push(v);
        }
      }
    }
  }

  for (int i = 1; i <= N; ++i) {
    if (!fwd[i] || !rev[i]) {
      std::cout << "No\n";
      return 0;
    }
  }

  std::vector<int> co(N + 1, -1);
  co[1] = 0;
  std::queue<int> q;
  q.push(1);
  int g = 0;
  while (!q.empty()) {
    int u = q.front();
    q.pop();
    for (int v : adj[u]) {
      if (co[v] == -1) {
        co[v] = co[u] + 1;
        q.push(v);
      } else {
        int diff = co[u] + 1 - co[v];
        g = std::gcd(g, std::abs(diff));
      }
    }
  }

  if (g == 0) {
    std::cout << "No\n";
    return 0;
  }
  if (g % 2 == 1) {
    std::cout << "Yes\n";
  } else {
    std::cout << "No\n";
  }
  return 0;
}