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
#!/usr/bin/env python                                                                                                                   
inputlist = map(str,raw_input().split())
numberlist = []
for a in inputlist:
    if a == "+":
        b = numberlist[-2]
	c = numberlist[-1]
	numberlist[-2:]=[]
	d = int(b) + int(c)
	numberlist.append(d)
    elif a == "-":
        b = numberlist[-2]
        c = numberlist[-1]
        numberlist[-2:]=[]
        d = int(b) - int(c)
        numberlist.append(d)
    elif a == "*":
	b = numberlist[-2]
        c = numberlist[-1]
        numberlist[-2:]=[]
        d = int(b) * int(c)
	numberlist.append(d)
    else:
        numberlist.append(a)
print(numberlist[0])