using System;

public class Solution {

    public static int LengthOfLastWord(string s) {

        int count = 0;

        for(int i=0;i<s.Length-1; i++ )

        {

            var currentChar = s[i]; 

            var nextChar = s[i+1];

            if(char.IsWhiteSpace(currentChar) && char.IsLetter(nextChar))

            {

                count = 1;

            }else

            {

                count++;

            }

        }

        return count;

    }

​

    public static void Main()

    {

        Console.WriteLine(LengthOfLastWord("Hello World a"));

    }

}