#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int n, m;
map<pair<int, int>, int> cnt;
vector<pair<int, int>> oc;
map<int, vector<pair<int, int>>> oks;
int getHighest(int x) {
  for (int i = 0; i < oc.size(); i++) {
    if (oc[i].second == x || cnt.count(make_pair(x, oc[i].second))) {
      continue;
    }
    return oc[i].first;
  }
  return 0;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m;
  map<int, int> occ;
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    cnt[make_pair(a, b)]++;
    cnt[make_pair(b, a)]++;
    occ[a]++;
    occ[b]++;
  }
  for (auto& p : cnt) {
    pair<int, int> q = p.first;
    int num = p.second;
    oks[q.first].push_back({q.second, num});
  }
  for (auto& p : occ) {
    oc.push_back({p.second, p.first});
  }
  sort(oc.begin(), oc.end(), greater<pair<int, int>>());
  for (int i = 1; i <= n; i++) {
    if (!occ.count(i)) continue;
    int maxans = occ[i] + getHighest(i);
    for (auto& p : oks[i]) {
      maxans = max(maxans, occ[i] + occ[p.first] - p.second);
    }
    if (maxans == m) {
      cout << "YES\n";
      return 0;
    }
  }
  cout << "NO\n";
}
