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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

'use strict';
 
process.stdin.resume();
process.stdin.setEncoding('utf-8');
 
let inputString = '';
let currentLine = 0;
 
process.stdin.on('data', function(inputStdin) {
    inputString += inputStdin;
});
 
process.stdin.on('end', function() {
    inputString = inputString.split('\n');
    main();
});
 
function readline() {
    return inputString[currentLine++];
}
 
 
// main function .... code start ... ///
function main() {
 
//var input = readline()

var k = readline().split(' ').map(x => parseInt(x));
var n = k[0], a = k[1], b = k[2];

var ok = 0;
if(n == 1){
    if(a == b)
        ok = 1;
    else
        ok = 0;
} 
else if(n > 1){
    if(a > b)
        ok = 0;
    else{
        ok = (b - a)*(n - 2) + 1;
    }
}

console.log(Math.max(ok , 0));

//

}