expression_evaluator

from collections import deque

expression = input().split()
result = deque()

for char in expression:
    if not char.lstrip('-').isdigit():
        while len(result) > 1:
            first_number = result.popleft()
            second_number = result.popleft()
            if char == "+":
                result.appendleft(first_number + second_number)
            elif char == "*":
                result.appendleft(first_number * second_number)
            elif char == "-":
                result.appendleft(first_number - second_number)
            elif char == "/":
                result.appendleft(first_number // second_number)

    else:
        result.append(int(char))
print(*result)