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 Rust (1.15.1) (judge verdict: Accepted)

fn read<T: std::str::FromStr>() -> T {
  let mut s = String::new();
  std::io::stdin().read_line(&mut s).ok();
  s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
  read::<String>().split_whitespace()
    .map(|e| e.parse().ok().unwrap()).collect()
}

fn read_vec2<T: std::str::FromStr>(n: u32) -> Vec<Vec<T>> {
  (0..n).map(|_| read_vec()).collect()
}

fn main() {
  let s: String = read();
  let s: &str = &s;

  let wd = ["SUN","MON","TUE","WED","THU","FRI","SAT"];

  let mut index: usize = 0;
  for (i, val) in wd.iter().enumerate() {
    if s == wd[i] {
      index = i;
      break;
    }
  }

  println!("{}", 7-index);
}