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using System;

namespace Test3
{
    class Stack
    {
        static int[] s;
        static int top;
        public Stack() {
            s = new int[2];
            top = -1;
        }
        public void push(int x) {
            if (top >= s.Length-1) {
                s = new int[s.Length * 2];
            }
            top++;
            s[top] = x;
        }
        public int pop() {
            top--;
            return s[top];
        }
        public void print() {
            for (int i = 0; i < s.Length; i++) {
                if (s[i] != 0) Console.Write(s[i]);
            }
            Console.WriteLine();
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            int[] data = { 1, 2, 3, 4, 5 };
            Stack s1 = new Stack();
            Stack s2 = new Stack();

            for (int i = 0; i < data.Length; i++)
            {
                s1.push(data[i]);
                s2.push(data[i]);
            }
            s1.pop(); s1.pop(); s1.pop();
            s2.pop();
            s1.print();
            s2.print();
        }
    }
}