#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

bool euler_path(vector<vector<int>> &g, int s = -1) {
    vector<int> cnt(2);
    for (auto &v: g) cnt[v.size() % 2]++;
    if (cnt[1] == 0) return true;
    if (cnt[1] == 2 && (s == -1 || g[s].size() % 2 == 1)) return true;
    return false;
}

int main() {
    int n, m; cin >> n >> m;
    vector<vector<int>> g(n);
    while (m--) {
        int a, b; cin >> a >> b;
        g[a].emplace_back(b);
        g[b].emplace_back(a);
    }
    cout << (euler_path(g) ? "YES" : "NO") << endl;
    return 0;
}