func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<vector<int> > solve(int N) {     vector<vector<int> > res(2, vector<int>(1, 1));     for (int n = 2, r = 0; n <= N; ++n) {       res[r].push_back(n);       ++r;       if (r >= int((res).size())) {         vector<int> new_row;         for (const vector<int>& r : res) new_row.push_back(r.back());         res.push_back(new_row);         r = 0;       }     }     return res;   }   int main(int argc, char* argv[]) {     ios_base::sync_with_stdio(false);     cin.tie(nullptr);     int N;     cin >> N;     vector<vector<int> > res = solve(N);     cout << int((res).size()) <<   n ;     for (const vector<int>& row : res) {       for (int x : row) cout << x <<    ;       cout <<   n ;     }     return 0;   }   