#include <bits/stdc++.h>
using namespace std;
long long F[200005];
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y % 2 != 0) res = res * x % p;
    y = y / 2;
    x = x * x % p;
  }
  return res;
}
long long ncr(long long n, long long r, long long p) {
  if (r > n) return 0;
  long long res = F[n];
  res = (res * power(F[r], p - 2ll, p)) % p;
  res = (res * power(F[n - r], p - 2ll, p)) % p;
  return res;
}
long long gcd(long long a, long long b) {
  if (a > b) swap(a, b);
  if (a == 0)
    return b;
  else
    return gcd(b % a, a);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n, m;
  cin >> n >> m;
  vector<pair<long long, long long>> a(m);
  for (long long i = 0; i < m; i++) cin >> a[i].first >> a[i].second;
  bool flag = false, f1 = true, f2 = true;
  long long x = a[0].first;
  long long cnt = 0;
  map<long long, long long> mp;
  for (long long i = 0; i < m; i++) {
    if (a[i].first != x && a[i].second != x) {
      f1 = false;
      cnt++;
      mp[a[i].first]++;
      mp[a[i].second]++;
    }
  }
  for (auto x : mp) {
    if (x.second == cnt) {
      flag = true;
    }
  }
  mp.clear();
  x = a[0].second;
  cnt = 0;
  for (long long i = 0; i < m; i++) {
    if (a[i].first != x && a[i].second != x) {
      f2 = false;
      cnt++;
      mp[a[i].first]++;
      mp[a[i].second]++;
    }
  }
  for (auto x : mp) {
    if (x.second == cnt) {
      flag = true;
    }
  }
  if (flag || f1 || f2)
    cout << "YES\n";
  else
    cout << "NO\n";
}
