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>
#pragma warning(disable : 4996)
using namespace std;
long long dp[18], pre;
long long pow(long long a, long long b) {
  long long re = 1;
  while (b > 0) {
    re *= a;
    b--;
  }
  return re;
}
long long go(long long x, long long len) {
  if (x == 0) return 1;
  long long re = 0;
  re += dp[len - 1];
  re += (x - (long long)pow(10LL, len - 1) + 1) * len;
  return re;
}
bool check(long long w, long long x, long long k) {
  long long len = 0, tem = x;
  while (tem) {
    len++;
    tem /= 10;
  }
  if ((double)(go(x, len) - pre) * (double)(k) - (double)w <= 0.0) return true;
  return false;
}
void Init() {
  dp[0] = 1;
  for (int i = (int)(1); i <= (int)(17); ++i) {
    dp[i] = dp[i - 1] + i * 9LL * (long long)pow(10LL, (long long)(i - 1));
  }
}
int main() {
  long long w, m, i, j, k, x, y, z, t, ca = 1, num = 0, re = 0;
  Init();
  scanf("%I64d%I64d%I64d", &(w), &(m), &(k));
  long long len = 0, tem = m;
  while (tem) {
    len++;
    tem /= 10;
  }
  if (len * k > w) {
    puts("0");
    return 0;
  }
  tem = m - 1;
  len = 0;
  while (tem) {
    len++;
    tem /= 10;
  }
  pre = go(m - 1, len);
  long long st = m, en = (long long)5e16;
  while (st + 1 < en) {
    long long mid = (st + en) >> 1;
    if (check(w, mid, k))
      st = mid;
    else
      en = mid;
  }
  printf("%I64d\n", st - m + 1);
  return 0;
}
