#include <bits/stdc++.h>
using namespace std;
const long long init = 1e9 + 7;
const long long N = 3e5 + 7;
vector<int> counts1(N, 0);
vector<pair<int, int> > v;
int m;
string solve(int x) {
  int c = 1, maxc = -1;
  for (int i = 1; i < m; ++i) {
    if (v[i].first == x || v[i].second == x) {
      ++c;
    } else {
      ++counts1[v[i].first];
      ++counts1[v[i].second];
      maxc = max(maxc, max(counts1[v[i].first], counts1[v[i].second]));
    }
  }
  if (c == m || maxc == m - c) {
    return "YES";
  }
  return "NO";
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n >> m;
  for (int i = 0; i < m; ++i) {
    int a, b;
    cin >> a >> b;
    v.push_back(make_pair(a, b));
  }
  string ans = solve(v[0].first);
  if (ans == "YES")
    cout << ans << endl;
  else {
    for (int i = 0; i <= n; ++i) counts1[i] = 0;
    ans = solve(v[0].second);
    cout << ans << endl;
  }
  return 0;
}
