Miscellany

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

namespace ConsoleApplication9
{
    class Program
    {
        static void Main(string[] args)
        {
            String s = Console.ReadLine();
            char[] chrs = s.ToCharArray();
            for (int i = 0; i < chrs.Length; i++)
            {
                if (chrs[i] == 'a' || chrs[i] == 'а')
                    chrs[i] = '*';
            }
            s=new String(chrs);
            Console.WriteLine(s);
        }
    }
}