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.util.Arrays;
import java.io.*;
import java.util.*;
public class task implements Runnable {
    public static void main(String[] args) {
        new Thread(new task()).run();
    }
    BufferedReader br;
    StringTokenizer in;
    PrintWriter out;
    public String nextToken() throws IOException {
        while (in == null || !in.hasMoreTokens()) {
            in = new StringTokenizer(br.readLine());
        }
        return in.nextToken();
    }
    public int nextInt() throws IOException {
        return Integer.parseInt(nextToken());
    }
    public long nextLong() throws IOException {
        return Long.parseLong(nextToken());
    }
    public double nextDouble() throws IOException {
        return Double.parseDouble(nextToken());
    }
    public int nextTime()throws IOException {   
        String s = nextToken();
        int hh = Integer.parseInt(s.substring(0,2));
        int mm = Integer.parseInt(s.substring(3,5));
        return hh*60 + mm; 
    }       
    public void printTime(int time){
        int h = time / 60;
        int m = time % 60;
        String s = ""; 
        if ( h < 10) s+="0";
        s+=h;
        s+=":";
        if ( m < 10) s+="0";
        s+=m;
        out.print(s);
    }   
    public void run() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
            solve();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(1);
        }
    }
    
    /////////////    

    public void solve() throws IOException {        
        int a = nextInt(),b = nextInt(), c= nextInt();
        for (int i = 0; i < 1000; ++i){
        	if ( b*i + b*c >= a*c) {out.println(i); break;} 
        }
        
   }
}