#include <bits/stdc++.h>
using namespace std;
template <class T>
int getbit(T s, int i) {
  return (s >> i) & 1;
}
template <class T>
T onbit(T s, int i) {
  return s | (T(1) << i);
}
template <class T>
T offbit(T s, int i) {
  return s & (~(T(1) << i));
}
template <class T>
int cntbit(T s) {
  return __builtin_popcount(s);
}
template <class T>
inline T gcd(T a, T b) {
  T r;
  while (b != 0) {
    r = a % b;
    a = b;
    b = r;
  }
  return a;
}
long long n, m, x, y, dd[300005];
pair<long long, long long> z[300005];
set<long long> s;
long long Rand(long long l, long long h) {
  return l +
         ((long long)rand() * (RAND_MAX + 1) * (RAND_MAX + 1) * (RAND_MAX + 1) +
          (long long)rand() * (RAND_MAX + 1) * (RAND_MAX + 1) +
          (long long)rand() * (RAND_MAX + 1) + rand()) %
             (h - l + 1);
}
void check(long long a, long long b) {
  for (long long i = 1, _b = m; i <= _b; i++) {
    if (z[i].first == a || z[i].first == b || z[i].second == a ||
        z[i].second == b)
      continue;
    return;
  }
  cout << "YES";
  exit(0);
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m;
  for (long long i = 1, _b = m; i <= _b; i++) cin >> z[i].first >> z[i].second;
  for (long long i = 1, _b = m; i <= _b; i++) {
    if (z[i].first > z[i].second) swap(z[i].first, z[i].second);
    s.insert(z[i].first);
    s.insert(z[i].second);
  }
  if (s.size() <= 2) {
    cout << "YES";
    return 0;
  }
  if (s.size() == 3) {
    vector<long long> v;
    for (auto x : s) v.push_back(x);
    check(v[0], v[1]);
    check(v[0], v[2]);
    check(v[1], v[2]);
    cout << "NO";
    return 0;
  }
  if (s.size() == 4) {
    vector<long long> v;
    for (auto x : s) v.push_back(x);
    check(v[0], v[1]);
    check(v[0], v[2]);
    check(v[0], v[3]);
    check(v[1], v[2]);
    check(v[1], v[3]);
    check(v[2], v[3]);
    cout << "NO";
    return 0;
  }
  check(z[1].first, z[1].second);
  for (long long i = 2, _b = m; i <= _b; i++) {
    if (z[i].first != z[1].first && z[i].first != z[1].second &&
        z[i].second != z[1].first && z[i].second != z[1].second) {
      vector<long long> v;
      v.push_back(z[i].first);
      v.push_back(z[1].first);
      v.push_back(z[i].second);
      v.push_back(z[1].second);
      check(v[0], v[1]);
      check(v[0], v[2]);
      check(v[0], v[3]);
      check(v[1], v[2]);
      check(v[1], v[3]);
      check(v[2], v[3]);
      cout << "NO";
      return 0;
    }
  }
  cout << "NO";
  return 0;
}
