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.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.StringTokenizer;



public class C219P2 {

    private static BufferedReader in;
    private static PrintWriter out;
    private static StringTokenizer input;
    
    public static void main(String[] args) throws IOException {
        //-------------------------------------------------------------------------
        //Initializing...
        new C219P2();
        //-------------------------------------------------------------------------
        //put your code here... :)
        long w = nextLong();
        long m = nextLong();
        long k = nextLong();
        
        
        
        
        writeln(""+play(w, m, k));
        //-------------------------------------------------------------------------
        //closing up
        end();
        //--------------------------------------------------------------------------

    }
    
    static long play(long w,long m,long k){
        int len = len(m);
        long upper = (long) Math.pow(10, len);
        long left = upper-m;
        long can = w/(k*len);
        if(left>=can) return can;
        w -= left*k*len;
        if(w<k*(len+1)) return left;
        return play(w,upper,k)+left;
    }
    
    
    private static int len(long m) {
        // TODO Auto-generated method stub
        return (""+m).length();
    }

    public C219P2() throws IOException {
        //Input Output for Console to be used for trying the test samples of the problem 
        in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);
        //-------------------------------------------------------------------------
        //Initalize Stringtokenizer input
        input = new StringTokenizer(in.readLine());
    }

    private static int nextInt() throws IOException {
        if (!input.hasMoreTokens())input=new StringTokenizer(in.readLine());
        return Integer.parseInt(input.nextToken());
    }
    private static long nextLong() throws IOException {
        if (!input.hasMoreTokens())input=new StringTokenizer(in.readLine());
        return Long.parseLong(input.nextToken());
    }
    private static double nextDouble() throws IOException {
        if (!input.hasMoreTokens())input=new StringTokenizer(in.readLine());
        return Double.parseDouble(input.nextToken());
    }
    private static String nextString() throws IOException {
        if (!input.hasMoreTokens())input=new StringTokenizer(in.readLine());
        return input.nextToken();
    }
    private static void write(String output){
        out.write(output);
        out.flush();
    }
    private static void writeln(String output){
        out.write(output+"\n");
        out.flush();
    }
    private static void end() throws IOException{
        in.close();
        out.close();
        System.exit(0);
    }

    

}
