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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>

int main() {

	int n, a, b, m;

	scanf("%d %d %d", &n, &a, &b);

	if (a > b) {
		m = 0;
	}
	else if(a==b){
		if (n == 1) {
				m = 1;
			}
			else {
				m = 0;
			}
		}

		else{
			if(n>1){
			m = (b - a)*(n - 2) + 1;
		}
		else {
			m = 0;
		}
	}
	printf("%d\n", m);
	return 0;

}