#include <stdio.h>
#include <stdlib.h>
#define STACKSIZE 20

typedef char info_t;
typedef struct s
{
info_t S[STACKSIZE];
int top;
} stack;

void init(stack *m)
{
m->top = -1;
}
void stackOverflow()
{
	fprintf(stderr, "ERROR: StackOverFlow\n");
	exit(-1);
}
void stackUnderflow()
{
	fprintf(stderr, "ERROR: StackUnderFlow\n");
	exit(-1);
}
void push(stack *m, info_t x)
{
if(m->top >= STACKSIZE)
	stackOverflow();
	m->S[++(m->top)]=x;

}
info_t pull(stack *m)
{
if(m->top < 0)
	stackUnderflow();
		return(m->S[(m->top)--]);
}
info_t Peek(stack *m)
{
if(m->top < 0)
	stackOverflow();
	return(m->S[(m->top)]); 
}
int isEmpty(stack *m)
{
	return((m->top) < 0);
}
int main()
{

return 0;
}