func_code_string: #include <bits/stdc++.h>   using namespace std;   int32_t main() {     ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);     long long n, m;     cin >> n >> m;     map<long long, set<long long>> adj;     for (long long i = 0; i < m; i++) {       long long a, b;       cin >> a >> b;       adj[a].insert(b);       adj[b].insert(a);     }     long long mx = INT_MIN, v = 0;     map<long long, long long> deg;     for (auto i : adj) {       deg[i.first] = i.second.size();       if (mx < i.second.size()) {         mx = i.second.size();         v = i.first;       }     }     deg[v] = 0;     for (auto i : adj[v]) {       deg[i]--;     }     long long f = 0;     for (long long i = 1; i <= n; i++) {       if (deg[i] > 0) {         f = 1;         break;       }     }     if (!f) {       cout <<  YES n ;       return 0;     }     mx = INT_MIN, v = 0;     for (long long i = 1; i <= n; i++) {       if (mx < deg[i]) {         mx = deg[i];         v = i;       }     }     deg[v] = 0;     for (auto i : adj[v]) {       deg[i]--;     }     f = 0;     for (long long i = 1; i <= n; i++) {       if (deg[i] > 0) {         f = 1;         break;       }     }     if (!f) {       cout <<  YES n ;       return 0;     }     cout <<  NO n ;     return 0;   }   