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

s=input().split()
q=deque()
op=["+","-","*"]
for i in s:
    if i in op:
        a=q.pop()
        b=q.pop()
        q.append(eval("b"+i+"a"))
    else:
        q.append(int(i))
print(q[0])
