Problem:
Day of Week

The 9th day of September 2017 is Saturday. Then, what day of the week is the X-th of September 2017?

Given a day in September 2017, write a program to report what day of the week it is.

Input

The input is given in the following format.

X

The input line specifies a day X (1 ≤ X ≤ 30) in September 2017.

Output

Output what day of the week it is in a line. Use the following conventions in your output: "mon" for Monday, "tue" for Tuesday, "wed" for Wednesday, "thu" for Thursday, "fri" for Friday, "sat" for Saturday, and "sun" for Sunday.

Sample Input 1

1

Sample Output 1

fri

Sample Input 2

9

Sample Output 2

sat

Sample Input 3

30

Sample Output 3

sat

Solution in C# (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace OthloKyopro
{
    class Program
    {
        static void Main(string[] args)
        {
            /* 101*/
            /*var a = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToList();
            var sum = 0;
            foreach(var i in a)
            {
                sum += i;
            }
            Console.WriteLine(sum / a.Count());
            */

            /* 2 */
            /*var input = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            var own = input[0];
            var a = input[1];
            var book = input[2];
            if(own >= book)
            {
                Console.WriteLine(0);
            }
            else if(own + a >= book)
            {
                Console.WriteLine(book - own);
            }
            else
            {
                Console.WriteLine("NA");
            }*/

            /*3*/
            var input = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray()[0];
            var mod = (input - 9) / 7;
            switch (mod)
            {
                case 0:
                    Console.WriteLine("sat");
                    break;
                case 1:
                    Console.WriteLine("sun");
                    break;
                case 2:
                    Console.WriteLine("mon");
                    break;
                case 3:
                    Console.WriteLine("tue");
                    break;
                case 4:
                    Console.WriteLine("wed");
                    break;
                case 5:
                    Console.WriteLine("thu");
                    break;
                default:
                    Console.WriteLine("fri");
                    break;
            }
        }
    }
}