#include <bits/stdc++.h>
using namespace std;
int N, M;
string S;
struct point {
  int x, y;
} p[300005];
struct pair1 {
  int key, value;
  bool operator<(pair1 pp) const { return value > pp.value; }
} counter[300005];
vector<point> remain;
vector<int> cand;
bool solution1() {
  for (int i = 0; i < N + 1; i++) counter[i].key = i;
  for (int i = 0; i < M; i++) {
    counter[p[i].x].value++, counter[p[i].y].value++;
  }
  sort(counter, counter + N + 1);
  for (int i = 0; i < 4; i++) {
    if (counter[i].value < M / 2) return 0;
    int m = counter[i].key;
    if (0) cout << "m=" << m << endl;
    remain.clear(), cand.clear();
    for (int j = 0; j < M; j++) {
      if (p[j].x != m && p[j].y != m) remain.push_back(p[j]);
    }
    if (remain.empty()) return 1;
    cand.push_back(remain[0].x), cand.push_back(remain[0].y);
    for (auto e : remain) {
      if (cand.size() > 1 && cand[1] != e.x && cand[1] != e.y)
        cand.erase(cand.begin() + 1);
      if (cand[0] != e.x && cand[0] != e.y) cand.erase(cand.begin());
      if (0) {
        for (auto sss : cand) cout << sss << " ";
        cout << endl;
      }
      if (cand.empty()) goto NEXT;
    }
    return 1;
  NEXT:;
  }
  return 0;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> N >> M;
  for (int i = 0; i < M; i++) cin >> p[i].x >> p[i].y;
  cout << (solution1() ? "YES" : "NO");
  return 0;
}
