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 C# (Mono-mcs 6.8.0.105) (judge verdict: Wrong Answer)

// C# program to build the smallest number 
// by removing n digits from a given number 
using System;
using System.Collections.Generic;
using System.Linq;
class GFG
{

    public static void Main(String[] args)
    {
        //  var n = long.Parse(Console.ReadLine());
        var input = Console.ReadLine().Split(' ');
        var a = long.Parse(input[0]);
        var b = long.Parse(input[1]);
        var n = long.Parse(input[2]);
        Floor(a, b, n);
    }

    public static void Floor(long a, long b, long n)
    {
        var max = 0;

       // for (int i = 1; i <= n; i++)
        {
            var t = Math.Floor(Convert.ToDecimal((a * n) / b)) - a * Math.Floor(Convert.ToDecimal(n / b));
            Console.Write(t);
        }

        Console.Write(max);
    }
}