func_code_string: #include <bits/stdc++.h>   #pragma comment(linker,  /STACK:64000000 )   using namespace std;   const int N6 = 1e6 + 6;   const int N9 = 1e9 + 7;   const long long INFLL = (long long)1e18 + 100;   const int INF = 1e9 + 100;   const long long mod = 1e9 + 9;   const long long P = 31;   int n, k, cur, ans;   std::vector<int> g[1111];   map<pair<int, int>, bool> cnt;   void solve() {     cin >> n >> k;     int cur;     for (int i = 1; i <= n; ++i) {       cur = 0;       for (int j = 1; j <= n; ++j) {         if (!cnt.count(make_pair(i, j)) && i != j) {           ++cur;           cnt[make_pair(i, j)];           cnt[make_pair(j, i)];           g[i].push_back(j);           ++ans;         }         if (cur == k) {           break;         }       }       if (cur != k) {         cout << -1;         exit(0);       }     }     cout << ans <<   n ;     for (int i = 1; i <= n; ++i) {       for (int j = 0; j < g[i].size(); ++j) {         cout << i <<     << g[i][j] <<   n ;       }     }   }   int main() {     int tt = 1;     while (tt--) {       solve();     }     return 0;   }   