#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)s; i < (int)e; ++i)
#define all(a) (a).begin(),(a).end()

struct UnionFind {
    vector<int> par, siz;
    int v, group;
    
    UnionFind(int n) {
        par = vector<int>(n, -1);
        siz = vector<int>(n, 1);
        v = n;
        group = n;
    }
    
    int root(int x) {
        if (par[x] == -1) return x;
        else return par[x] = root(par[x]);
    }
    
    bool same(int x, int y) {
        return root(x) == root(y);
    }
    
    bool unite(int x, int y) {
        x = root(x);
        y = root(y);
        
        if (x == y) return false;
        
        if (siz[x] < siz[y]) swap(x, y);
        par[y] = x;
        siz[x] += siz[y];
        group--;
        return true;
    }
    
    int size(int x) {
        return siz[root(x)];
    }
};

int main() {
    cin.tie(nullptr);
    
    int N, M;
    cin >> N >> M;
    
    UnionFind uf(N * 2);
    rep(i, 0, M) {
        int A, B;
        cin >> A >> B;
        A--, B--;
        uf.unite(2*A, 2*B + 1);
        uf.unite(2*A + 1, 2*B);
    }
    
    bool ok = true;
    rep(i, 0, N) if (!uf.same(2*i, 2*i + 1)) ok = false;
    
    if (ok) cout << "Yes\n";
    else cout << "No\n";
}