#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long int a, b, c, d, e, p = -1, q = -1, r = -1, s = -1, flag, maxx = 0,
                               minn = 10000000000;
  cin >> a >> b;
  long long int A[b][2];
  for (c = 0; c < b; c++) {
    cin >> A[c][0] >> A[c][1];
    if (maxx < min(A[c][0], A[c][1])) {
      p = A[c][0];
      q = A[c][1];
      maxx = min(A[c][0], A[c][1]);
    }
    if (minn > max(A[c][0], A[c][1])) {
      r = A[c][0];
      s = A[c][1];
      minn = max(A[c][0], A[c][1]);
    }
  }
  if (p == r || p == s || q == r || q == s)
    cout << "YES" << endl;
  else {
    flag = 1;
    for (c = 0; c < b; c++) {
      if (p != A[c][0] && q != A[c][0] && p != A[c][1] && q != A[c][1]) {
        flag = 0;
        break;
      }
    }
    if (flag) {
      cout << "YES" << endl;
      return 0;
    }
    flag = 1;
    for (c = 0; c < b; c++) {
      if (p != A[c][0] && r != A[c][0] && p != A[c][1] && r != A[c][1]) {
        flag = 0;
        break;
      }
    }
    if (flag) {
      cout << "YES" << endl;
      return 0;
    }
    flag = 1;
    for (c = 0; c < b; c++) {
      if (p != A[c][0] && s != A[c][0] && p != A[c][1] && s != A[c][1]) {
        flag = 0;
        break;
      }
    }
    if (flag) {
      cout << "YES" << endl;
      return 0;
    }
    flag = 1;
    for (c = 0; c < b; c++) {
      if (q != A[c][0] && r != A[c][0] && q != A[c][1] && r != A[c][1]) {
        flag = 0;
        break;
      }
    }
    if (flag) {
      cout << "YES" << endl;
      return 0;
    }
    flag = 1;
    for (c = 0; c < b; c++) {
      if (q != A[c][0] && s != A[c][0] && q != A[c][1] && s != A[c][1]) {
        flag = 0;
        break;
      }
    }
    if (flag) {
      cout << "YES" << endl;
      return 0;
    }
    flag = 1;
    for (c = 0; c < b; c++) {
      if (r != A[c][0] && s != A[c][0] && r != A[c][1] && s != A[c][1]) {
        flag = 0;
        break;
      }
    }
    if (flag) {
      cout << "YES" << endl;
      return 0;
    }
    cout << "NO" << endl;
  }
}
