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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

main = function(input) {
    var data = input.split("\n").join(" ").split(" ");
    var n = data[0];
    var a = data[1];
    var b = data[2];
    
    var ans = (n - 2) * (b - a) + 1;
    
    
    console.log(Math.max(parseInt(ans), parseInt(0)));
};

main(require("fs").readFileSync("/dev/stdin", "utf8"));