using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        IDictionary<char, int> charecters = new Dictionary<char, int>();

​

        charecters.Add('S', 1);

        charecters.Add('N', 2);

​

        char expression = 'A';

        if (charecters.ContainsKey(expression))

        {

            Console.WriteLine(charecters[expression]);

        } 

        else

        {

            Console.WriteLine(3);

        }

    }

}