#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long TESTS = 1;
  while (TESTS--) {
    long long n, m;
    cin >> n >> m;
    vector<pair<long long, long long> > v(m);
    for (long long i = 0; i < m; i++) {
      cin >> v[i].first >> v[i].second;
    }
    vector<pair<long long, long long> > va;
    long long a = v[0].first, b = v[0].second;
    for (long long i = 1; i < m; i++) {
      if (v[i].first != a && v[i].second != a)
        va.push_back({v[i].first, v[i].second});
    }
    if ((long long)va.size() == 0) {
      cout << "YES";
      return 0;
    }
    long long c = va[0].first;
    long long flag = 1;
    for (long long i = 1; i < (long long)va.size(); i++) {
      if (va[i].first != c && va[i].second != c) {
        flag = 0;
        break;
      }
    }
    if (flag == 1) {
      cout << "YES";
      return 0;
    }
    long long d = va[0].second;
    flag = 1;
    for (long long i = 1; i < (long long)va.size(); i++) {
      if (va[i].first != d && va[i].second != d) {
        flag = 0;
        break;
      }
    }
    if (flag == 1) {
      cout << "YES";
      return 0;
    }
    va.clear();
    for (long long i = 1; i < m; i++) {
      if (v[i].first != b && v[i].second != b)
        va.push_back({v[i].first, v[i].second});
    }
    if ((long long)va.size() == 0) {
      cout << "YES";
      return 0;
    }
    c = va[0].first;
    flag = 1;
    for (long long i = 1; i < (long long)va.size(); i++) {
      if (va[i].first != c && v[i].second != c) {
        flag = 0;
        break;
      }
    }
    if (flag == 1) {
      cout << "YES";
      return 0;
    }
    d = va[0].second;
    flag = 1;
    for (long long i = 1; i < (long long)va.size(); i++) {
      if (va[i].first != d && va[i].second != d) {
        flag = 0;
        break;
      }
    }
    if (flag == 1) {
      cout << "YES";
      return 0;
    }
    cout << "NO";
  }
  return 0;
}
