#!/usr/bin/perl

use strict;


my @PRINT_STACK;
my @OP_STACK;

my $x = 0;
my $temp;

#print $x,$x++,$x++;

push @OP_STACK, $x++;                                     # push the last $x++ to the operator stack (pushes 0)
print "OP_STACK => ( ",@OP_STACK, " )\n";

push @OP_STACK, $x++;                                     # push the next $x++ operator to the operator stack (pushes 1)
print "OP_STACK => ( ",join(", ",@OP_STACK)," )\n";

# All Operations are over 

$temp = pop @OP_STACK;                                    #pop The operator stack and push it to print stack (pops 1)
push @PRINT_STACK, $temp;                                 # pushes 1
print "PRINT_STACK => ( ",join(", ",@PRINT_STACK)," )\n";

$temp = pop @OP_STACK;                                    #pop The operator stack and push it to print stack (pops 0)
push @PRINT_STACK, $temp;                                 #pushes 0
print "PRINT_STACK => ( ",join(", ",@PRINT_STACK)," )\n";

push @PRINT_STACK, $x;                                    # push the first $x to the operator stack (pushes 2)
print "PRINT_STACK => ( ",join(", ",@PRINT_STACK)," )\n";

print pop @PRINT_STACK;
print pop @PRINT_STACK;
print pop @PRINT_STACK;

exit();