#include <bits/stdc++.h>
using namespace std;

#define _p(...) (void)printf(__VA_ARGS__)
#define forr(x,arr) for(auto&& x:arr)
#define _overload3(_1,_2,_3,name,...) name
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload3(__VA_ARGS__,_rep3,_rep2,)(__VA_ARGS__)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__)
#define ALL(x) (x).begin(), (x).end()
#define BIT(n) (1LL<<(n))
#define SZ(x) ((int)(x).size())
#define fst first
#define snd second
typedef vector<int> vi;typedef vector<vi> vvi;typedef pair<int,int> pii;typedef vector<pii> vpii;
typedef long long ll;

void Main() {
  int N, M;
  scanf("%d%d", &N, &M);
  vvi E(N);
  vpii es(M);

  vector<bool> d1(N);
  vector<bool> d2(N);

  rep(i, M) {
    int u, v;
    scanf("%d%d", &u, &v);
    u--; v--;
    E[u].push_back(v);
    E[v].push_back(u);
    if (u > v) swap(u, v);
    es[i] = {u, v};
    if (u == 0) d1[v] = 1;
  }

  rep(i, M) {
    int u = es[i].fst;
    int v = es[i].snd;
    if (d1[u] == 1 && v != 0) d2[v] = 1;
    if (d1[v] == 1 && u != 0) d2[u] = 1;
  }

  //cout << "d1:"; rep(ii,SZ(d1)) cout << ' ' << d1[ii]; cout << endl;
  //cout << "d2:"; rep(ii,SZ(d2)) cout << ' ' << d2[ii]; cout << endl;

  rep(i, M) {
    int u = es[i].fst;
    int v = es[i].snd;
    if (d2[u] && d2[v]) {
      set<int> c;
      forr(nc, E[u]) if (nc != u && nc != v && d1[nc]) {
        c.insert(nc);
      }
      forr(nc, E[v]) if (nc != u && nc != v && d1[nc]) {
        c.insert(nc);
      }
      if (SZ(c) >= 2) {
        puts("YES");
        return;
      }
    }
  }
  puts("NO");
}
int main() { cin.tie(0); ios::sync_with_stdio(false); Main(); return 0; }