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
#!/usr/bin/env python
from __future__ import division, print_function
from sys import stdin
exppression = stdin.readline().split()
stack = []
while exppression:
    token = exppression.pop(0)
    if token.isdigit():
        stack.append(int(token))
    elif token == '+':
        n = stack.pop()
        stack[-1] += n
    elif token == '-':
        n = stack.pop()
        stack[-1] -= n
    else:
        n = stack.pop()
        stack[-1] *= n
print(stack[-1])