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 OCaml (4.02.3) (judge verdict: Accepted)

let id x = x
let (n,a,b) = Scanf.scanf "%d %d %d\n" (fun n a b -> (n,a,b))
 
let ans = if b-a < 0 || (b-a > 0 && n=1) then 0
    else if a=b then 1
    else (b-a) * (n-2) +1

let () =
  Printf.printf "%d\n" ans