993 992 991
 100 1 10
 960 935 994
 99 8 99
 60 16 1
 759 10 258
 24 19 9
 196 169 144
 1000 999 1
 945 812 917
 1000 100 10
 500 300 300
 888 777 1000
 2 1 4
 24 12 12
 767 2 514
 2 1 2
 1000 1 1
 5 2 1
 70 32 1
 765 123 899
 17 7 10
 5 4 10
 888 777 888
 66 38 4
 1000 999 1000
 9 3 300
 244 87 4
 765 123 45
 1000 1 1000
 305 203 421
 100 10 1
 64 12 8
 894 1 999
 2 1 1
 18 14 10
 6 2 4
 888 777 1
 27 26 1
 2 1 3
 5 1 5
 7 3 200
 561 31 917
 17 10 7
 93 74 831

1
 990
 27
 1127
 3
 19325
 3
 24
 1
 151
 90
 200
 143
 4
 12
 196605
 2
 999
 2
 2
 4693
 15
 3
 127
 3
 2
 600
 8
 235
 999000
 212
 9
 35
 892107
 1
 3
 8
 1
 1
 3
 20
 267
 15678
 5
 214

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.StringTokenizer;


public class Main
{
    static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    static PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
    static StringTokenizer datos = new StringTokenizer(""); 

    public static String next() throws IOException
    {
        while(!datos.hasMoreTokens()){
            String s = in.readLine();
            if(s==null) return null;
            datos = new StringTokenizer(s);
        }
        return datos.nextToken();
    }
    
    public static int nextInt() throws IOException
    {
        return Integer.parseInt(next());
    }
    
    public static void main(String[] args)throws IOException
    {
        int a = nextInt();
        int b = nextInt();
        int c = nextInt();
        int l = 0;
        int r = (a * c) / b;
        int res = Integer.MAX_VALUE;
        w:while(l<=r){
            int mid = l + (r - l) / 2;
            int datos = mid * b;
            for(int i=0;i<=c;i++){
                if(datos<i*a){
                    l = mid + 1;
                    continue w;
                }
                datos += b;
            }
            res = Math.min(res, mid);
            r = mid - 1;
        }
        out.println(res);
        out.flush();
    }
}
