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 getans(long long x) {
  long long cmp = 10;
  long long add = 9;
  long long ans = 0;
  long long sum = 0;
  long long cnt = 1;
  while (x >= cmp) {
    sum += add;
    ans += add * cnt;
    cnt++;
    add *= 10;
    cmp *= 10;
  }
  ans += (x - sum) * cnt;
  return ans;
}
inline long long getval(long long x) { return (getans(x) - getans(m - 1)); }
long long binarysearch(long long l, long long r, long long val) {
  if (l == r) {
    while (getval(l) > val) l--;
    return l;
  }
  long long mid = (l + r) >> 1;
  if (getval(mid) < val)
    return binarysearch(mid + 1, r, val);
  else
    return binarysearch(l, mid, val);
}
int main() {
  while (cin >> w >> m >> k) {
    long long t = binarysearch(m, 100000000000000000, w / k);
    if (t < m)
      puts("0");
    else
      cout << t - m + 1 << endl;
  }
  return 0;
}
