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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

import Data.List

day :: [String]
day = ["SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"]

main = print =<< ((pure nextDay) <*> getLine)

nextDay :: String -> Int
nextDay s = (8 - ) $ (+ 1) $ (\(Just t) -> t) $ elemIndex s day