func_code_string: #include <bits/stdc++.h>   using namespace std;   int dcount(long long i) {     int c = 0;     while (i > 0) {       i = i / 10;       c++;     }     return c;   }   int main() {     long long n, cnt = 0;     cin >> n;     int num = dcount(n);     for (long long int i = 0; i < num; i++) {       cnt += n > (pow(10, i + 1) - 1) ? (pow(10, i + 1) - pow(10, i)) * (i + 1)                                       : (n - pow(10, i) + 1) * (i + 1);     }     cout << cnt;   }   