#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<n; ++i)
#define repl(i,m,n) for(ll i=m; i<n; ++i)

struct UnionFind{
    vector<int> size, parent;

    UnionFind(){}
    UnionFind(int n){
        size.resize(n,0);
        parent.resize(n,0);
        for(int i=0; i<n; ++i){
            make_tree(i);
        }
    }

    void make_tree(int x){
        parent[x] = x;
        size[x] = 1;
    }

    bool is_same(int x, int y){
        return find_root(x) == find_root(y);
    }

    bool unite(int x, int y){
        x = find_root(x);
        y = find_root(y);
        if(x == y) return false;
        if(size[x] > size[y]){
            parent[y] = x;
            size[x] += size[y];
        }else{
            parent[x] = y;
            size[y] += size[x];
        }
        return true;
    }

    int find_root(int x){
        if(x != parent[x]) parent[x] = find_root(parent[x]);
        return parent[x];
    }

    int tree_size(int x){
        return size[find_root(x)];
    }
};

int main(){
    int N, L;
    cin >> N >> L;

    UnionFind uf(2*N);
    rep(i, 0, L){
        int A, B;
        cin >> A >> B;
        A--, B--;
        uf.unite(A, B+N);
        uf.unite(A+N, B);
    }

    bool f = true;
    rep(i, 0, N){
        if(!uf.is_same(i, i+N)){
            f = false;
            break;
        }
    }
    cout << (f ? "Yes" : "No") << endl;

    return 0;
}