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

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
#define rep3(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define rep2(i, a, b) rep3(i, a, b, 1)
#define rep1(i, n) rep2(i, 0, n)
#define rep0(n) rep1(aaaaa, n)
#define ov4(a, b, c, d, name, ...) name
#define rep(...) ov4(__VA_ARGS__, rep3, rep2, rep1, rep0)(__VA_ARGS__)
#define per(i, a, b) for (ll i = (a) - 1; i >= (b); i--)
#define fore(e, v) for (auto &&e : v)
#define all(a) begin(a), end(a)
#define sz(a) (int)(size(a))
#define lb(v, x) (lower_bound(all(v), x) - begin(v))
#define eb emplace_back

template <typename T, typename S> bool chmin(T &a, const S &b) {
  return a > b ? a = b, 1 : 0;
}
template <typename T, typename S> bool chmax(T &a, const S &b) {
  return a < b ? a = b, 1 : 0;
}
const int INF = 1e9 + 100;
const ll INFL = 3e18 + 100;
#define i128 __int128_t
struct _ {
  _() { cin.tie(0)->sync_with_stdio(0), cout.tie(0); }
} __;

int main() {
  int N, M, K;
  cin >> N >> M >> K;
  atcoder::scc_graph G(N);
  vector E(N, vi());
  rep(M) {
    int U, V;
    cin >> U >> V;
    --U, --V;
    G.add_edge(U, V);
    E[U].push_back(V);
  }
  auto scc = G.scc();
  vi comp(N);
  rep(i, sz(scc)) {
    for (auto v : scc[i])
      comp[v] = i;
  }

  auto ng = [&]() {
    cout << "No\n";
    exit(0);
  };

  vi dist(N, INF);
  vector DAGe(sz(scc), set<int>());
  rep(i, N) {
    if (dist[i] < INF)
      continue;
    dist[i] = 0;
    int c = comp[i];
    if (sz(scc[c]) == 1)
      continue;
    queue<int> bfs;
    bfs.push(i);
    bool ok = 0;
    while (!bfs.empty()) {
      int v = bfs.front();
      bfs.pop();
      for (auto u : E[v]) {
        if (comp[u] == comp[v]) {
          if (dist[u] > dist[v] + 1) {
            dist[u] = dist[v] + 1;
            bfs.push(u);
          } else {
            if (dist[u] % 2 == dist[v] % 2)
              ok = 1;
          }
        } else {
          DAGe[c].insert(comp[u]);
        }
      }
    }
    if (!ok)
      ng();
  }
  if (comp[0] != 0)
    ng();
  if (sz(scc[0]) == 1)
    ng();
  rep(i, sz(scc) - 1) if (sz(scc[i]) == 1 && sz(scc[i + 1]) == 1) ng();
  rep(i, sz(scc) - 1) if (!DAGe[i].contains(i + 1)) ng();
  cout << "Yes\n";
}