func_code_string: #include <bits/stdc++.h>   using namespace std;   long long t, d, ct, q, ans, l, m, r, n, mx, mn, i, j, k, x, y, z, s;   char ch;   string ss =   , str =   ;   map<pair<long long, long long>, long long> mp;   set<long long> st;   long long a[300003], b[300003];   vector<pair<long long, long long>> v;   bool ask(long long k) {     long long i;     for (i = 0; i < v.size(); i++)       if (v[i].first != k && v[i].second != k) break;     if (i == v.size()) return 1;     long long x = v[i].first;     long long g = k;     if (x > k) swap(x, k);     if (a[x] + a[k] - mp[{x, k}] == m) return 1;     x = v[i].second;     if (x > g) swap(x, g);     if (a[x] + a[g] - mp[{x, g}] == m) return 1;     return 0;   }   int main() {     ios_base::sync_with_stdio(false), cin.tie(nullptr);     s = k = d = l = mx = m = mn = r = q = i = j = z = x = y = ct = ans = 0;     cin >> n >> m;     for (i = 0; i < m; i++) {       cin >> x >> y, a[x]++, a[y]++;       v.push_back({x, y});       if (x > y) swap(x, y);       mp[{x, y}]++;     }     x = v[0].first;     y = v[0].second;     bool ya = ask(x);     if (ya) {       cout <<  YES ;       return 0;     }     ya = ask(y);     if (ya) {       cout <<  YES ;       return 0;     }     cout <<  NO ;     return 0;   }   