#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef int _loop_int;
#define REP(i,n) for(_loop_int i=0;i<(_loop_int)(n);++i)
#define FOR(i,a,b) for(_loop_int i=(_loop_int)(a);i<(_loop_int)(b);++i)
#define FORR(i,a,b) for(_loop_int i=(_loop_int)(b)-1;i>=(_loop_int)(a);--i)

#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define DEBUG_VEC(v) cout<<#v<<":";REP(i,v.size())cout<<" "<<v[i];cout<<endl
#define ALL(a) (a).begin(),(a).end()

#define CHMIN(a,b) a=min((a),(b))
#define CHMAX(a,b) a=max((a),(b))

// mod
const ll MOD = 1000000007ll;
#define FIX(a) ((a)%MOD+MOD)%MOD

// floating
typedef double Real;
const Real EPS = 1e-11;
#define EQ0(x) (abs(x)<EPS)
#define EQ(a,b) (abs(a-b)<EPS)
typedef complex<Real> P;

int n,m;
vi g[25252];

int color[25252];
int dp[25252][16];
int dfs(int p,int msk){
  if(dp[p][msk]!=-1)return dp[p][msk];
  if(p==0 && msk==15)return 1;
  if(p==0 && msk!=0)return 0;
  int nmsk = msk;
  if(p==0){
    if(msk==15)return dp[p][msk]=1;
    if(msk!=0)return dp[p][msk]=0;
  }else{
    int c = color[p];
    if((msk>>c)&1){
      return dp[p][msk]=0;
    }else{
      nmsk = msk | (1<<c);
    }
  }
  REP(i,g[p].size()){
    int to = g[p][i];
    if(dfs(to,nmsk)==1){
      return dp[p][msk]=1;
    }
  }
  return dp[p][msk]=0;
}

// color coding

uint32_t xorshift(void) {
  static uint64_t x = 88172645463325252ULL;
  x = x ^ (x << 13); x = x ^ (x >> 7);
  return x = x ^ (x << 17);
}

int main(){
  scanf("%d%d",&n,&m);
  REP(i,m){
    int a,b;
    scanf("%d%d",&a,&b);--a;--b;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  bool flag = false;
  REP(_,30){
    REP(i,n){
      color[i] = (xorshift())&3;
      REP(j,16)dp[i][j]=-1;
    }
    if(dfs(0,0)==1){
      flag = true;
      break;
    }
    // REP(i,n){
    //   printf("%d :",i);
    //   REP(j,16)printf("%4d",dp[i][j]);
    //   printf("\n");
    // }
  }
  puts(flag?"YES":"NO");
  return 0;
}