Problem:
Score : 400 points

Problem Statement

Given are integers A, B, and N.

Find the maximum possible value of floor(Ax/B) - A × floor(x/B) for a non-negative integer x not greater than N.

Here floor(t) denotes the greatest integer not greater than the real number t.

Constraints

1 ≤ A ≤ 10^{6}

1 ≤ B ≤ 10^{12}

1 ≤ N ≤ 10^{12}

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B N

Output

Print the maximum possible value of floor(Ax/B) - A × floor(x/B) for a non-negative integer x not greater than N, as an integer.

Sample Input 1

5 7 4

Sample Output 1

2

When x=3, floor(Ax/B)-A×floor(x/B) = floor(15/7) - 5×floor(3/7) = 2. This is the maximum value possible.

Sample Input 2

11 10 9

Sample Output 2

9

Solution in Java (OpenJDK 11.0.6) (judge verdict: Runtime Error)

import java.util.Scanner;

public class Main {

   public static void main(String args[]) {


      Scanner scan = new Scanner(System.in);

      int a = scan.nextInt();
      int b = scan.nextInt();
      int n = scan.nextInt();

      int max = 0;

     for (int i = 0; i <= n; i++) {
        int ans;

        int floor1 = a * i / b;

        int floor2 = i / b;

        ans = floor1 - a * floor2;

        if (max < ans) {
            max = ans;
        }
     }

     System.out.println(String.valueOf(max));


}
}