#include <bits/stdc++.h>
const int M = 1e9 + 7;
long long mod(long long x) { return ((x % M + M) % M); }
long long add(long long a, long long b) { return mod(mod(a) + mod(b)); }
long long mul(long long a, long long b) { return mod(mod(a) * mod(b)); }
using namespace std;
long long gcd(int x, int y) {
  if (y == 0) return x;
  return gcd(y, x % y);
}
long long power(int x, int y) {
  if (y == 0) return 1;
  long long t = power(x, y / 2);
  if (y % 2 == 1) return x * t * t;
  return t * t;
}
double findMod(double a, double b) {
  double mod;
  if (a < 0)
    mod = -a;
  else
    mod = a;
  if (b < 0) b = -b;
  while (mod >= b) mod = mod - b;
  if (a < 0) return -mod;
  return mod;
}
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long modInverse(long long n, long long p) { return power(n, p - 2, p); }
long long ans = INT_MIN;
void dfs(vector<int> adj[], vector<int> &vis, int i, int &f) {
  vis[i] = 1;
  for (auto it = adj[i].begin(); it != adj[i].end(); it++) {
    if (!vis[*it]) {
      f++;
      dfs(adj, vis, *it, f);
    }
  }
}
vector<pair<int, int>> v;
bool ok(int x, int y) {
  for (pair<int, int> p : v) {
    if (p.first != x && p.second != y && p.first != y && p.second != x)
      return false;
  }
  return true;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, k;
  cin >> n >> k;
  for (int i = 0; i < k; i++) {
    int a, b;
    cin >> a >> b;
    v.emplace_back(a, b);
  }
  for (int x : {v[0].first, v[0].second}) {
    if (ok(x, -1)) {
      cout << "yes" << endl;
      return 0;
    }
    for (int i = 1; i < k; i++) {
      if (v[i].first != x && v[i].second != x) {
        if (ok(x, v[i].first) || ok(x, v[i].second)) {
          cout << "yes" << endl;
          return 0;
        }
        break;
      }
    }
  }
  cout << "no";
}
