#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> P;
int main(){
    int n,m;cin>>n>>m;
    set<P> al;
    std::vector<int> cnt(n);
    for(int i=0;i<m;i++){
        int a,b;cin>>a>>b;
        assert(1<=a&&a<=n);
        assert(1<=b&&b<=n);
        assert(a!=b);
        al.insert(P(min(a,b),max(a,b)));
        cnt[a-1]++;cnt[b-1]++;
    }
    assert(al.size()==m);
    vector<int> cnt2(n);
    for(int i=0;i<n;i++)cnt2[cnt[i]]++;
    for(int i=0;i<n;i++){
        if(cnt2[i]>1){
            cout<<"Yes"<<endl;return 0;
        }
    }
    cout<<"No"<<endl;
}