#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); }

// res.first = 強連結成分の個数
// res.second[v] = v が属する強連結成分の番号
pair<int, V<int>> scc(int n, V<V<int>> g){
  int tm = 0, it = 0, idx = 0;
  V<int> ord(n, -1), st(n + 1, n), id(n, n);
  auto dfs = [&](auto& dfs, int v) -> int {
    int low = ord[v] = tm++;
    st[it++] = v;
    for (auto w : g[v]) if(id[w] >= n)
      chmin(low, ord[w] < 0 ? dfs(dfs, w) : ord[w]);
    if (low == ord[v] && ++idx)
      while(st[it] != v) id[st[--it]] = idx;
    return low;
  };
  REP(i, n) if (ord[i] == -1) dfs(dfs, i);
  for(auto& x : id) x = idx - x;
  return make_pair(idx, move(id));
}

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);
  }
  auto [sz, gid] = scc(n, g);
  V<V<int>> groups(sz);
  REP(u, n) {
    groups[gid[u]].push_back(u);
    for(int v : g[u]) {
      if(gid[u] == gid[v]) continue;
      if(gid[u]+1 == gid[v]) continue;
      cout << "No\n";
      return;
    }
  }
  V<int> odd(sz);
  V<V<int>> seen(2, V<int>(n));
  REP(gi, sz) {
    int st = groups[gi][0];
    stack<pair<int, int>> stk;
    seen[0][st] = 1;
    stk.emplace(0, st);
    while(!stk.empty()) {
      auto [d, u] = stk.top(); stk.pop();
      for(int v : g[u]) {
        if(gid[u] != gid[v]) continue;
        if(seen[d^1][v]) continue;
        seen[d^1][v] = 1;
        stk.emplace(d^1, v);
      }
    }
    odd[gi] = seen[1][st];
    if(odd[gi]) continue;
    if(gi > 0 && k == 1 && odd[gi-1]) continue;
    cout << "No\n";
    return;
  }
  cout << "Yes\n";
}

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