def push(x):
	global stack

	stack.append(x)

def pop():
	global stack

	ret = stack.pop()
	return ret

ope = {"+": lambda a, b: b + a,
	   "-": lambda a, b: b - a,
	   "*": lambda a, b: b * a}

if __name__ == '__main__':
	stack = []

	for c in input().split():
		if c in ope:
			push(ope[c](pop(), pop()))
		else:
			push(int(c))

	print(" ".join(map(str, stack)))