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
input_num=input().split()
num=[]

for i in input_num:
	if i=='+' or i=='-' or i=='*' or i=='/':
		n1=int(num.pop())
		n2=int(num.pop())
		
		if i=='+':
			num.append(n2+n1)
		elif i=='-':
			num.append(n2-n1)
		elif i=='*':
			num.append(n2*n1)
		else:
			num.append(n2/n1)
	else:
		num.append(int(i))
print(num[0])
