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
A = raw_input().split()
B = []
def add(x, y):
    return x + y
def sub(x, y):
    return x - y
def mul(x, y):
    return x * y
operation = {'+':add, '-':sub, '*':mul}
for item in A:
    if item.isdigit():
        B.append(int(item))
    else:
        num2 = B.pop() 
        num1 = B.pop()
        ans = operation[item](num1, num2)
        B.append(ans)
print ans