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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Linq;
public class Hello{
    public static void Main(){
        var input = Console.ReadLine().Split(' ').Select(long.Parse).ToArray();
        var n = input[0];
        var a = input[1];
        var b = input[2];
        var max = 0L;
        var min = 0L;
        if(n >= 1 && a <= b){
            max = a + b * (n - 1);
            min = a * (n - 1) + b;
            Console.WriteLine(max - min + 1);
        }else{
            Console.WriteLine(0);
        }
        
    }
}