using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Please enter a sentence.");

        string sentence = Console.ReadLine();

        Console.WriteLine("Please enter a letter.");

        string letter = Console.ReadLine();

        int ocounter = 0;

        int x = 0;

        while (x <= sentence.Length-1)

        {

            if (sentence[x].ToString() == letter)

            {

                ocounter++;             

            }

            x++;

        }

    Console.WriteLine("There are " +ocounter+ letter "'s in the sentence.");

    }

}