Program to Count number of Vowels and consonants from a given String

/*
 * C# Program to Count number of Vowels and consonants from a given String
 */
using System;
class program
{
    public static void Main()
    {
        char[] sentence = new char[100];

        int i, vowels = 0, consonants = 0, special = 0, n;
        Console.WriteLine("Enter the Length of the sentence  \n");
        n = int.Parse(Console.ReadLine());
        for (i = 0; i < n; i++)
        {
            sentence[i] = Convert.ToChar(Console.Read());
        }
        for (i = 0; sentence[i] != '\0'; i++)
        {
            if ((sentence[i] == 'a' || sentence[i] == 'e' || sentence[i] ==
            'i' || sentence[i] == 'o' || sentence[i] == 'u') ||
            (sentence[i] == 'A' || sentence[i] == 'E' || sentence[i] ==
            'I' || sentence[i] == 'O' || sentence[i] == 'U'))
            {
                vowels = vowels + 1;
            }
            else
            {
                consonants = consonants + 1;
            }
            if (sentence[i] == 't' || sentence[i] == '\0' || sentence[i] == ' ')
            {
                special = special + 1;
            }
        }

        consonants = consonants - special;
        Console.WriteLine("No. of vowels {0}", vowels);
        Console.WriteLine("No. of consonants {0}", consonants);
        Console.ReadLine();
        Console.ReadLine();
    }
}