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("*number")
local l = io.read("*number")
local b = io.read("*number")

local sum = 0
if l ~= b and n < 2 then
	print(sum)
 	return sum
end

if l > b then
	print(sum)
	return sum
end

local minx = (n - 1)*l + b
local maxx = (n-1)*b + l

local sum = maxx - minx + 1
print(sum)