using System;

    using System.Collections.Generic;               

public class Program

{

    public static void Main()

    {

        List<int>vaska=new List<int>();

        Stack<int>a=new Stack<int>(6);

        a.Push(1);

        a.Push(2);

        a.Push(3);

        a.Push(7);

        a.Push(49);

        a.Push(18);

        foreach(int i in a)

        {Console.Write(i+" ");}

        for(int i=0; i<6; i++){

            if(a.Peek()%3==0 && a.Peek()%7==0)

            {}}

    }

}