#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

int main() {
  int n, m; cin >> n >> m;
  dsu uf(2 * n);
  for (int i = 0; i < m; i++) {
    int a, b; cin >> a >> b;
    a--, b--;
    uf.merge(a, n + b);
    uf.merge(b, n + a);
  }
  for (int i = 0; i < n; i++) {
    if (uf.same(i, i + n)) continue;
    cout << "No" << endl;
    return 0;
  }
  cout << "Yes" << endl;
  return 0;
}