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
l=[0]*1000
c=0
s=input().split()
for i in s:
	if i=="+":
		l[c-2]=l[c-2]+l[c-1]
		c=c-1
	elif i=="-":
		l[c-2]=l[c-2]-l[c-1]
		c=c-1
	elif i=="*":
		l[c-2]=l[c-2]*l[c-1]
		c=c-1
	else:
		l[c]=int(i)
		c=c+1
print(l[0])
