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
# encoding: utf-8

input = raw_input().split()

stack = []
for n in input:
    if(n.isdigit()):
        stack.append(int(n))
    else:
        a = stack.pop()
        b = stack.pop()
        if n == '+':
            stack.append(b + a)
        elif n == '-':
            stack.append(b - a)
        elif n == '*':
            stack.append(b * a)
        else:
            stack.append(b / a)
print stack.pop()