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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func solve() {
	days := [7]string{"SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"}
	s := getString()

	ans := -1
	for i, d := range days {
		if s == d {
			ans = 7 - i
		}
	}
	fmt.Fprintln(wr, ans)
}

// -----------------------------------------

const (
	inf = 1 << 60
	// mod = 1000000007
)

var (
	sc = bufio.NewScanner(os.Stdin)
	wr = bufio.NewWriter(os.Stdout)
)

func main() {
	// buf := 200001
	// sc.Buffer(make([]byte, buf), buf)
	sc.Split(bufio.ScanWords)
	solve()
	wr.Flush()
}

func getInt() int {
	sc.Scan()
	i, err := strconv.Atoi(sc.Text())
	if err != nil {
		panic(err)
	}
	return i
}

func getIntSlice(n int) []int {
	is := make([]int, n)
	for i := range is {
		is[i] = getInt()
	}
	return is
}

func getString() string {
	sc.Scan()
	s := sc.Text()
	return s
}

func getRunes() []rune {
	return []rune(getString())
}