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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {

	static Scanner sc = new Scanner(System.in);
    public void run() throws Exception {
    	//StringBuilder sb = new StringBuilder();

    	int n1 = sc.nextInt();
    	int n2 = sc.nextInt();
    	int n3 = sc.nextInt();
    	long anw = 0;
    	if(n1 == 1){
    		if(n2 > n3){
    			anw = 0;
    		}else if (n2 == n3){
    			long min = n2*(n1-1) + n3;
            	long max = n3*(n1-1) + n2;
            	anw = max - min + 1;
    		}
    	}else {
        	long min = n2*(n1-1) + n3;
        	long max = n3*(n1-1) + n2;
        	anw = max - min + 1;
    	}
    	System.out.println(anw);
    }
    public static void main(String[] args) throws Exception {
        new Main().run();
    }
}