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 = list(map(str, input().split(" ")))
op = {"+":lambda x, y:x+y, "-":lambda x,y:x-y, "*":lambda x,y:x*y}
stack = []

for i, z in enumerate(A):
    if z not in op:
        stack.append(z)
        continue
    y = int(stack.pop())
    x = int(stack.pop())
    stack.append(op[z](x,y))
print(stack[0])
    
    
    
