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,i,j,sum=0,d;
 scanf("%d %d %d",&n,&i,&j);
 if(n==1){
    if(i!=j) sum=0;
    else sum=1;
 }
 if(n>1){
    if(i>j) sum=0;
    if(i==j) sum=1;
    else{
        d=j-i;
        sum=(n-2)*d+1;
    }
 }
printf("%d",sum);
return 0;
}