Notes

Template in C

Constraints

2 ≤ the number of operands in the expression ≤ 100
1 ≤ the number of operators in the expression ≤ 99
-1 × 109 ≤ values in the stack ≤ 109

Input

An expression is given in a line. Two consequtive symbols (operand or operator) are separated by a space character.

You can assume that +, - and * are given as the operator and an operand is a positive integer less than 106

Output

Print the computational result in a line.

Examples

Input

1 2 +


Output

3


Input

1 2 + 3 4 - *


Output

-3
# coding: utf-8
from collections import deque

inputs = deque(raw_input().split())
q = deque()
while len(inputs):
    op = inputs.popleft()
    if op == '+':
        q.append(q.pop() + q.pop())
    elif op == '-':
        v1 = q.pop()
        v2 = q.pop()
        q.append(v2 - v1)
    elif op == '*':
        q.append(q.pop() * q.pop())
    else:
        q.append(int(op))

print q.pop()

