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
#python2.7

A=raw_input().split()
B=[]
for i in A:
	if i.isdigit():
		B.append(i)
	else:
		if i=="+":
			B[-1]=str(int(B[-1])+int(B[-2]))
			del B[-2]
		elif i=="-":
			B[-1]=str(int(B[-2])-int(B[-1]))
			del B[-2]
		elif i=="*":
			B[-1]=str(int(B[-1])*int(B[-2]))
			del B[-2]
print B[0]