#include <bits/stdc++.h>
using namespace std;
int ct[300005];
vector<pair<int, int> > val;
int n, m;
bool check(int vl) {
  for (int i = 0; i < 300005; i++) ct[i] = 0;
  int count = 0;
  for (int i = 0; i < m; i++) {
    if (vl != val[i].first && vl != val[i].second) {
      count++;
      ct[val[i].first]++;
      if (val[i].second != val[i].first) {
        ct[val[i].second]++;
      }
    }
  }
  if (count == 0) return true;
  for (int i = 1; i < 300001; i++) {
    if (ct[i] == count) {
      return true;
    }
  }
  return false;
}
int main() {
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    val.push_back(make_pair(a, b));
  }
  int first = val[0].first;
  int second = val[0].second;
  if (check(first)) {
    cout << "YES\n";
  } else if (check(second)) {
    cout << "YES\n";
  } else {
    cout << "NO\n";
  }
}
