func_code_string: #include <bits/stdc++.h>   using namespace std;   long long a[20];   long long b[20];   int getbit(long long x) {     int ret = 0;     while (x) {       x /= 10;       ++ret;     }     return ret;   }   int main() {     a[1] = 9;     b[1] = 9;     for (int i = 2; i <= 18; ++i) b[i] = b[i - 1] * 10 + 9;     for (int i = 2; i <= 18; ++i) a[i] = a[i - 1] * 10;     long long w, m, k;     while (cin >> w >> m >> k) {       long long num = getbit(m);       long long cnt = b[num] - m + 1;       long long ans = 0;       if (w <= num * k * cnt || (num * k * cnt) <= 0) {         ans = w / (num * k);       } else {         ans = cnt;         w -= cnt * num * k;         for (int i = num + 1; w > 0; ++i) {           if (w <= a[i] * i * k || a[i] * i * k <= 0) {             ans += w / (i * k);             break;           } else {             ans += a[i];             w -= a[i] * k * i;           }         }       }       cout << ans << endl;     }     return 0;   }   