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




import java.io.*;
import java.util.*;
import java.lang.*;

public final class Main {
    static final long lim_m = (long) (double) 1e17;
    static class O {
        //sum_digits(n): [Naive] for(i,1,n) sum += number_of_digit(n)
        static long numDigit(long n) {
        		//giống sumDigit nhưng khoảng(1, n)
						long result = 0;
            for(long i = 1; i <= n; i*=10){
            		result+= n - i + 1;
            }
            return result;
        }
        static long sumDigit(long a, long b) {
							if(a > b){
              		long temp = a;
                  a = b;  
                  b = a;
              }
              return numDigit(b) - numDigit(a);
        }
        static long run() {
            Scanner in = new Scanner(System.in);
            long w, m, k;
            w = in.nextLong();
            m = in.nextLong();
            k = in.nextLong();
						
            w /= k;
            
            long l, r, mid;
            l = m;
            r = (long) (double) 1e17 + 1;
            if (w < (long) Math.log10(m) + 1) {
                return 0;
            }
            while(l < r-1){
            		mid = (l+r)/2;
                    // System.out.println(l + " " + mid + " " + r);
            		if(O.sumDigit(m-1, mid) <= w){
                		l = mid;
                } else {
                		r = mid;
                }
            }
            // System.out.println(l + " " + m);
            return l- m +1;
        }
    }
    public static void main(String[] args) {
        System.out.println(O.run());
    }

}







