Problem:
Score : 200 points

Problem Statement

Snuke has N integers. Among them, the smallest is A, and the largest is B.
We are interested in the sum of those N integers. How many different possible sums there are?

Constraints

1 ≤ N,A,B ≤ 10^9

A and B are integers.

Input

Input is given from Standard Input in the following format:

N A B

Output

Print the number of the different possible sums.

Sample Input 1

4 4 6

Sample Output 1

5

There are five possible sums: 18=4+4+4+6, 19=4+4+5+6, 20=4+5+5+6, 21=4+5+6+6 and 22=4+6+6+6.

Sample Input 2

5 4 3

Sample Output 2

0

Sample Input 3

1 7 10

Sample Output 3

0

Sample Input 4

1 3 3

Sample Output 4

1

Solution in Kotlin (1.3.71) (judge verdict: Wrong Answer)

import java.util.*

fun main(args: Array<String>) {
  val sc = Scanner(System.`in`)
  val n = sc.nextLong()
  val a = sc.nextLong()
  val b = sc.nextLong()

  if (n == 1L && a < b) {
    println(0)
    return
  }
  if (a > b) {
    println(0)
    return
  }
  if (n != 1L && a == b) {
    println(1)
    return
  }
  if (n == 2L) {
    println(1)
    return
  }

  val min =  a + a + a + b
  val max =  a + b + b + b
  println(max - min + 1L)



}