using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
 
namespace ConsoleApplication1
{
    class Program
    {
        static char[] A={'a','b','c'};
        static int N = 3;
        static void foo(string s)
        {
            if (s.Length == N)
            {
                Console.WriteLine(s);
                return;
            }
            for (int i = 0; i < A.Length; i++)
            {
                string t = s;
                t += A[i];
                foo(t);
            }
        }
 
        static void Main(string[] args)
        {
            foo("");
        }
    }
}
 

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