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;
const long long INF = 100000000000000000LL;
long long w, M, k;
long long ans;
long long calcS(long long x) {
  if (x < 10) return x;
  long long ret = 0;
  long long i = 1, bit = 1;
  for (; i * 10 <= x; i *= 10, ++bit) ret += bit * i * 9;
  long long digit = x / i % 10;
  ret += (digit - 1) * i * bit;
  ret += (x % i + 1) * bit;
  return ret;
}
int main() {
  cin >> w >> M >> k;
  for (long long l = 0, r = INF - M; l <= r;) {
    long long m = (l + r) / 2;
    if ((calcS(M + m - 1) - calcS(M - 1)) <= w / k)
      ans = m, l = m + 1;
    else
      r = m - 1;
  }
  cout << ans << endl;
  return 0;
}
