#include<bits/stdc++.h>
#include <atcoder/all>
#ifdef LOCAL
#include <debug_print.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
using namespace atcoder;
using mint=modint1000000007;
using namespace std;
using ll=long long;
using ul=unsigned long long;
int dx[9] = {-1, 1, 0, 0, -1, -1, 1, 1, 0};
int dy[9] = {0, 0, -1, 1, -1, 1, -1, 1, 0};
using Graph=vector<vector<int>>;
ll op(ll a,ll b){return min(a,b);}
ll e(){return 2e9;}
int main(){
	int N,M;
	cin>>N>>M;
	dsu uf(N);
	bool ok=false;
	for(int i=0;i<M;i++){
		int a,b;
		cin>>a>>b;
		a--,b--;
		if(uf.same(a,b))ok=1;
		uf.merge(a,b);
	}
	if(ok&&uf.groups().size()==1)cout<<"Yes"<<endl;
	else cout<<"No"<<endl;
}