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 Scala (2.13.1) (judge verdict: Runtime Error)


object Main extends App {
  val abn =  scala.io.StdIn.readLine()
  val abnArray = abn.split(" ").map(_.toInt).toSeq
  val a = abnArray(0).toLong
  val b = abnArray(1).toLong
  val n = abnArray(2).toLong

  var tempMax = 0L

  (0L to n).foreach { x =>
    val temp1 = a * x / b
    val temp2 = x / b
    val tempResult = temp1 - a * temp2
    if(tempMax < tempResult) {
      tempMax = tempResult
    }

  }
  println(tempMax)
}