func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<int> a[10005];   int main() {     int n, x, k = 0;     cin >> n;     x = (sqrt(1.0 + 8 * n) + 1) / 2;     cout << x << endl;     for (int i = 1; i <= x; i++)       for (int j = i + 1; j <= x; j++) a[i].push_back(++k), a[j].push_back(k);     for (int i = 1; i <= x; i++, cout << endl)       for (int j = 0; j < a[i].size(); j++) cout << a[i][j] <<    ;     return 0;   }   