Problem:
Score : 100 points

Problem Statement

Given is a string S representing the day of the week today.

S is SUN, MON, TUE, WED, THU, FRI, or SAT, for Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday, respectively.

After how many days is the next Sunday (tomorrow or later)?

Constraints

S is SUN, MON, TUE, WED, THU, FRI, or SAT.

Input

Input is given from Standard Input in the following format:

S

Output

Print the number of days before the next Sunday.

Sample Input 1

SAT

Sample Output 1

1

It is Saturday today, and tomorrow will be Sunday.

Sample Input 2

SUN

Sample Output 2

7

It is Sunday today, and seven days later, it will be Sunday again.

Solution in JavaScript (node.js v5.12) (judge verdict: Accepted)

function main(input){
	const reverse = (s) => {
        return s.split('').reverse().join('');
    };

  const WEEK = ['SUN','MON','TUE','WED','THU','FRI','SAT'].map(reverse);
  const S = reverse(input.split('\n')[0]);

	var index = 0;
	for (var i=0 ; i<=WEEK.length ; i++) {
			if (WEEK[i] === S) {
              	index = 7-i
				console.log(index)
				break;
			}
	}

}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));