We'll define S(n) for positive integer n as follows: the number of the n's digits in the decimal base. For example, S(893) = 3, S(114514) = 6.

You want to make a consecutive integer sequence starting from number m (m, m + 1, ...). But you need to pay S(n)·k to add the number n to the sequence.

You can spend a cost up to w, and you want to make the sequence as long as possible. Write a program that tells sequence's maximum length.

Input

The first line contains three integers w (1 ≤ w ≤ 1016), m (1 ≤ m ≤ 1016), k (1 ≤ k ≤ 109).

Please, do not write the %lld specifier to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams or the %I64d specifier.

Output

The first line should contain a single integer — the answer to the problem.

Examples

Input

9 1 1


Output

9


Input

77 7 7


Output

7


Input

114 5 14


Output

6


Input

1 1 2


Output

0
#include <bits/stdc++.h>
using namespace std;
long long w, m, k;
long long temp1(long long x) {
  long long y = 0;
  while (x > 0) {
    x /= 10;
    y++;
  }
  return y;
}
long long temp2(long long x) {
  long long num = 1;
  for (int i = 1; i <= x; i++) num *= 10;
  return num;
}
int main() {
  long long sum;
  while (~scanf("%lld%lld%lld", &w, &m, &k)) {
    long long a = temp1(m);
    long long t = w / k;
    long long t1 = t / a;
    long long t2 = temp2(a);
    long long ans = 0;
    while (t > 0) {
      if (t1 > t2 - m) {
        t -= (t2 - m) * a;
        ans += t2 - m;
        a++;
        t1 = t / a;
        t2 = temp2(a);
        m = temp2(a - 1);
      } else {
        t -= t1 * a;
        ans += t1;
        break;
      }
    }
    printf("%lld\n", ans);
  }
  return 0;
}
