#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;

int main()
{
    int N, M;
    cin >> N >> M;
    vector<vector<int>> G(N);
    for (int i = 0; i < M; i++)
    {
        int A, B;
        cin >> A >> B;
        A--;
        B--;
        G[A].push_back(B);
        G[B].push_back(A);
    }
    vector<int> P(N, -1);
    bool ok = true;
    auto dfs = [&](auto dfs, int v, int p) -> void
    {
        P[v] = p;
        int self = P[v];

        for (auto nv : G[v])
        {
            if (P[nv] == -1)
            {
                dfs(dfs, nv, P[nv]);
            }
            else if (self == P[nv])
            {
                ok = false;
            }
        }
    };
    for (int i = 0; i < N; i++)
    {
        if (P[i] == -1)
        {
            dfs(dfs, i, 0);
        }
    }
    if (ok)
    {
        cout << "Yes";
    }
    else
    {
        cout << "No";
    }
}