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 Lua (Lua 5.3.5) (judge verdict: Accepted)

local n, a, b = io.read("n", "n", "n")

if n == 1 and a == b then
	print(1)
	os.exit()
elseif n == 1 then
	print(0)
	os.exit()
elseif a > b then
	print(0)
	os.exit()
end

print((n - 2) * (b - a) + 1)