/*
 * postfix.c
 *
 *    simple postfix expression evaluator.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int stack [1000];
int top;

int
eval (char *s);

int
isop (char op);

int
pop (void);

void
push (int a);

int
do_op (int a, int b, char op);

int
main (void)
{
	char s [85];

	while (gets (s) != NULL) {
		printf ("%d\n", eval (s));
	}

	return 0;
}

int
eval (char *s)
{
	char *ptr;
	int first, second, c;

	ptr = strtok (s, " ");
	top = -1;

	while (ptr) {
		if (isop (*ptr))  {
			second = pop ();
			first = pop ();
			
			c = do_op (first, second, *ptr);
			push (c);
		}
		else {
			c = atoi (ptr);
			push (c);
		}

		ptr = strtok (NULL, " ");
	}

	return (pop ());
}

int
do_op (int a, int b, char op)
{
	int ans;

	switch (op) {
	case '+':
		ans = a + b;
		break;
	case '-':
		ans = a - b;
		break;
	case '*':
		ans = a * b;
		break;
	}

	return ans;
}


int
pop (void)
{
	int ret;

	ret = stack [top];
	top--;

	return ret;
}

void
push (int a)
{
	top++;
	stack [top] = a;
}

int
isop (char op)
{
	if (op == '+' || op == '-' || op == '*')
		return 1;
	else
		return 0;
}