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
from collections import deque

def main():
    S = raw_input().split()
    D = deque([])
    for s in S:
        if s == '+':
            b = D.pop()
            a = D.pop()
            D.append(a+b)   
        elif s == '-':
            b = D.pop()
            a = D.pop()
            D.append(a-b)
        elif s == '*':
            b = D.pop()
            a = D.pop()
            D.append(a*b)
        else:
            D.append(int(s))
    print D.pop()
    return 0

main()