MAX_SIZE = 5
stack = [None] * MAX_SIZE
top = -1  # -1 indicates the stack is currently empty

def push(item):
    global top
    # 1. Check for Overflow (Is the array full?)
    if top >= MAX_SIZE - 1:
        print("Error: Stack Overflow!")
        return False
    
    # 2. Increment top pointer FIRST
    # We must move the pointer to the next empty slot before inserting
    top += 1
    
    # 3. Insert item at the new top position
    stack[top] = item
    return True

def pop():
    global top
    # 1. Check for Underflow (Is the array empty?)
    if top == -1:
        print("Error: Stack Underflow!")
        return None
    
    # 2. Retrieve the item currently at the top
    item = stack[top]
    
    # 3. Decrement top pointer AFTER retrieval
    # The item remains in memory, but is logically removed from our stack
    top -= 1
    return item

#include <iostream>
using namespace std;

const int MAX_SIZE = 5;
int stack[MAX_SIZE];
int top = -1; // -1 indicates the stack is currently empty

bool push(int item) {
    // 1. Check for Overflow (Is the array full?)
    if (top >= MAX_SIZE - 1) {
        cout << "Error: Stack Overflow!" << endl;
        return false;
    }
    
    // 2. Increment top pointer FIRST
    // We must move the pointer to the next empty slot before inserting
    top++;
    
    // 3. Insert item at the new top position
    stack[top] = item;
    return true;
}

int pop() {
    // 1. Check for Underflow (Is the array empty?)
    if (top == -1) {
        cout << "Error: Stack Underflow!" << endl;
        return -1; // Assuming -1 indicates error for this example
    }
    
    // 2. Retrieve the item currently at the top
    int item = stack[top];
    
    // 3. Decrement top pointer AFTER retrieval
    // The item remains in memory, but is logically removed from our stack
    top--;
    return item;
}