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
import sys

stack = []

array = sys.stdin.readline().strip().split(" ")

for op in array:
    if op.isdigit():
        stack.append(int(op))
    else:
        tmp1 = stack.pop()
        tmp2 = stack.pop()
        if op == "+":
            stack.append(tmp1 + tmp2)
        elif op == "-":
            stack.append(tmp2 - tmp1)
        elif op == "*":
            stack.append(tmp1 * tmp2)
        elif op == "/":
            stack.append(float(tmp2) / tmp1)
res = stack.pop()
print str(int(res))