#include <iostream>
#include <vector>

using namespace std;

int main(){
	int N, M;
	while(cin >> N >> M){
		vector<int> num(N, 0);
		for(int i=0;i<2*M;i++){
			int a; cin >> a;
			num[a-1]++;
		}
		bool ok = true;
		for(int i=0;i<N;i++) if(num[i]%2) ok = false;
		cout << (ok ? "YES" : "NO") << endl;
	}
}
