#include <iostream>
#include <vector>
#include <algorithm>
#include <bit>
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define bw(x) bit_width(unsigned(x))
#define no() { cout << "no\n"; return 0; }

using namespace std;

int main() {
    cin.tie(0)->sync_with_stdio(0);

    int n, m;
    cin >> n >> m;

    vector<vector<int>> adj(n);
    rep(i, 0, m) {
        int a, b; cin >> a >> b;
        --a, --b;
        adj[a].emplace_back(b);
        adj[b].emplace_back(a);
    }

    int d = bw(n) - 1;
    if (!(n == (1 << d) && ranges::all_of(adj, [d](auto& v) { return v.size() == d; }))) no()

    rep(i, 0, n) sort(all(adj[i]));

    auto check_edge = [&](int u, int v) {
        vector<int> intersection;
        set_intersection(all(adj[u]), all(adj[v]), back_inserter(intersection));
        return intersection.size() == 0;
    };

    rep(u, 0, n)
        for (auto v : adj[u])
            if (!check_edge(u, v)) no()
    cout << "yes\n";
}