#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
  long long n, m;
  cin >> n >> m;
  map<long long, set<long long>> adj;
  for (long long i = 0; i < m; i++) {
    long long a, b;
    cin >> a >> b;
    adj[a].insert(b);
    adj[b].insert(a);
  }
  long long mx = INT_MIN, v = 0;
  map<long long, long long> deg;
  for (auto i : adj) {
    deg[i.first] = i.second.size();
    if (mx < i.second.size()) {
      mx = i.second.size();
      v = i.first;
    }
  }
  deg[v] = 0;
  for (auto i : adj[v]) {
    deg[i]--;
  }
  long long f = 0;
  for (long long i = 1; i <= n; i++) {
    if (deg[i] > 0) {
      f = 1;
      break;
    }
  }
  if (!f) {
    cout << "YES\n";
    return 0;
  }
  mx = INT_MIN, v = 0;
  for (long long i = 1; i <= n; i++) {
    if (mx < deg[i]) {
      mx = deg[i];
      v = i;
    }
  }
  deg[v] = 0;
  for (auto i : adj[v]) {
    deg[i]--;
  }
  f = 0;
  for (long long i = 1; i <= n; i++) {
    if (deg[i] > 0) {
      f = 1;
      break;
    }
  }
  if (!f) {
    cout << "YES\n";
    return 0;
  }
  cout << "NO\n";
  return 0;
}
