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

/* -
Legends - A: An Array.
          S: A String Array
          n: Size of the Array A.
          x: an integer variable.
The List of Functions in the Library
1. Take input in an Integer Array - ob.ar_iin(n);
1.5 Take input in an Long Array - ob.sr_lin(n);
2. Take input in an String Array - ob.ar_sin(n);
3. Take input in an Character Array - ob.ar_cin(n);
4. Take input in an Double Array - ob.ar_din(n);
5. Print the content of an int Array - ob.print_iarr(A);
6. Print the content of an String Array - ob.print_sarr(A);
7. Print the content of a Character Array - ob.print_carr(A);
8. Print the content of a Double Array - ob.print_darr(A);
9. Get the sum of an Integer Array - ob.ar_sum(A);
10. Get the Maximum in an Array  - ob.ar_max(A);
12. Get the Minimum in an Array - ob.ar_min(A);
13. Get the Number of Digits in an Integer - ob.idigits(x);
14. Get an Integer Input - ob.iin();
15. Get a String Input - ob.sin();
*/

import java.io.*;
import java.util.*;
public class football
{

// Write Your Program in the main method below! 
  public static void main(String args[])throws Exception
  {
    football ob = new football();
    int A[] = ob.ar_iin(3);
    int a = A[0]; int b = A[1]; int c = A[2];   
    System.out.println(ob.bsearch(a,b,c));
  }

  public int bsearch(int a, int b, int c)
  {
      football ob = new football();
      int l = 0;
      int h = a*c;
      while(l<=h)
      {
          int mid = (l+h)/2;
          int res = ob.chkbuffer(a,b,c,mid);
          if(res==1)  
           h = mid-1;
          else
           l = mid+1;
      }
      return (int)((h/b)+1);
  }

  public int chkbuffer(int a,int b,int c,int data)
  {
      int str_buff = c*b;
      int watched = data+str_buff;
    if(watched<(a*c))
      return -1;
    else
     return 1;
  }

  // *********** Below are the library functions, just refer the Legends at the start of the Program to use them.

  public int iin()throws Exception
  {
    DataInputStream in = new DataInputStream(System.in);
    int n = Integer.parseInt(in.readLine());
    return n;
  }
  
  public String sin()throws Exception
  {
    DataInputStream in = new DataInputStream(System.in);
    String s = in.readLine();
    return s;
  }
          
  public int[] ar_iin(int n)throws Exception
  { //Take Integer Array as Input
    DataInputStream in = new DataInputStream(System.in);
    //int n = Integer.parseInt(in.readLine());
    String line = in.readLine();
    int A[] = new int[n];
    String strs[] = line.trim().split(" ");
    for(int i=0;i<n;i++)
     A[i] = Integer.parseInt(strs[i]);
    return A;
  }

  public long[] ar_lin(int n)throws Exception
  { //Take Long Array as Input
    DataInputStream in = new DataInputStream(System.in);
    String line = in.readLine();
    long A[] = new long[n];
    String strs[] = line.trim().split(" ");
    for(int i=0;i<n;i++)
     A[i] = Long.parseLong(strs[i]);
    return A;
  }

  public String[] ar_sin(int n)throws Exception
  { //Take Integer Array as Input
    DataInputStream in = new DataInputStream(System.in);
    //int n = Integer.parseInt(in.readLine());
    String line = in.readLine();
    String strs[] = line.trim().split(" ");
    return strs;
  }

  public char[] ar_cin(int n)throws Exception
  { //Take Integer Array as Input
    DataInputStream in = new DataInputStream(System.in);
    //int n = Integer.parseInt(in.readLine());
    String line = in.readLine();
    char A[] = new char[n];
    String strs[] = line.trim().split(" ");
    for(int i=0;i<n;i++)
     A[i] = (strs[i]).charAt(0);
    return A;
  }

  public double[] ar_din(int n)throws Exception
  { //Take Integer Array as Input
    DataInputStream in = new DataInputStream(System.in);
    //int n = Integer.parseInt(in.readLine());
    String line = in.readLine();
    double A[] = new double[n];
    String strs[] = line.trim().split(" ");
    for(int i=0;i<n;i++)
     A[i] = Double.parseDouble(strs[i]);
    return A;
  }

  public void print_iarr(int A[]){
  	for(int i=0;i<A.length;i++)
  	 System.out.print(A[i]+" ");
  	System.out.println();
  }

  public void print_sarr(String A[]){
  	for(int i=0;i<A.length;i++)
  	 System.out.print(A[i]+" ");
  	System.out.println();
  }

  public void print_carr(char A[]){
  	for(int i=0;i<A.length;i++)
  	 System.out.print(A[i]+" ");
  	System.out.println();
  }

  public void print_darr(double A[]){
  	for(int i=0;i<A.length;i++)
  	 System.out.print(A[i]+" ");
  	System.out.println();
  }
  public int ar_sum(int A[])
  { //Find sum of element in an Array
    int sum=0;
    for(int i=0;i<A.length;i++)
     sum=sum+A[i];
    return sum;
  }

  public int ar_max(int A[])
  {
    int max=A[0];
    for(int i=0;i<A.length;i++)
     max=max>A[i]?max:A[i];
    return max;
  }

  public int ar_min(int A[])
  {
    int min=A[0];
    for(int i=0;i<A.length;i++)
     min=min<A[i]?min:A[i];
    return min;
  }

  public int idigits(int n)
  {
    return (int)Math.floor(Math.log10(n) + 1);
  }

  public int[] freq(String n)
  {
    n=n.toLowerCase();
    int A[] = new int[26];
    int len = n.length();
    for(int i=0;i<len;i++){
      char a = n.charAt(i);
      int temp = (int)a;
      int val = temp-97;
      A[val]++;
    }
    return A;
  }

}
