#include <stdio.h>
#include <stdlib.h>

#define MAX_STACK_SIZE 50

int stack[MAX_STACK_SIZE],
    sp = MAX_STACK_SIZE;

int push(int);
int pop();

int main(void)
{

    return 0;
}

int push(int number)
{
    if (sp)
    {
        stack[--sp] = number;
        return sp;
    }
    else
    {
        printf("\nStack overflow\n");
        return -1;
    }
}

int pop()
{
    if (sp < MAX_STACK_SIZE)
        return stack[sp++];
    else
    {
        printf("\nStack empty\n");
        return -1;
    }
}