#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

struct UnionFind{
    vector<int> p;
    UnionFind(int n): p(vector<int>(n, -1)){}

    int root(int x){
        if(p[x] < 0) return x;
        else return p[x] = root(p[x]);
    }

    int size(int x){
        return -p[root(x)];
    }
    
    bool same(int x, int y){
        return root(x) == root(y);
    }

    void unite(int x, int y){
        if(same(x, y)) return;
        x = root(x);
        y = root(y);
        if(size(x) < size(y)) swap(x, y);
        p[x] += p[y];
        p[y] = x;
    }
};

int main(){
    int n, m; cin >> n >> m;
    UnionFind uf(n*2);
    for(int i = 0; i < m; i++){
        int a, b; cin >> a >> b;
        a--; b--;
        uf.unite(a, n+b);
        uf.unite(n+a, b);
    }

    for(int i = 0; i < n; i++){
        if(!uf.same(i, n+i)){
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
    return 0;
}