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 (5.3.2) (judge verdict: Accepted)

local n = io.read('*n')
local a = io.read('*n')
local b = io.read('*n')
if b < a then
	print(0)
	return
end
if n == 1 then
	if a ~= b then
		print(0)
		return
	else
		print(1)
		return
	end
elseif n == 2 then
	print(1)
	return
end
print((n-2)*(b-a)+1)