func_code_string: #include <bits/stdc++.h>   using namespace std;   long long w, m, k;   int main() {     scanf( %I64d%I64d%I64d , &w, &m, &k);     w /= k;     if (!w) {       puts( 0 );       return 0;     }     long long cnt = 0;     long long tmp = m;     while (tmp) {       cnt++;       tmp /= 10;     }     tmp = 1;     for (int i = 0; i < cnt; i++) tmp *= 10;     long long x = m - 1, y = tmp - 1;     while (w) {       if (w < cnt) break;       if (w >= (y - x) * cnt) {         w -= (y - x) * cnt;         x = y;         y = y * 10 + 9;         cnt++;       } else {         x += w / cnt;         w = 0;         break;       }     }     cout << x - m + 1 << endl;   }   