#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
#include <ranges>
#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()

    vector assigned(n, false);
    assigned[0] = true;
    vector p(n, -1);
    p[0] = 0;
    for (queue<int> bfs({0}); !bfs.empty(); bfs.pop()) {
        int u = bfs.front();
        auto unassigned = ranges::filter_view(adj[u], [&](int v) { return p[v] == -1; });
        vector q(all(unassigned));
        rep(j, 0, d) {
            if (assigned[p[u] | (1 << j)]) continue;
            if (q.empty()) no()
            int v = q.back();
            q.pop_back();
            p[v] = p[u] | (1 << j);
            assigned[p[v]] = true;
            bfs.push(v);
        }
    }

    rep(u, 0, n)
        for (auto v : adj[u])
            if (popcount(unsigned(p[u] ^ p[v])) != 1) no()

    cout << "yes\n";
}