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
s=list(map(str,input().split()))
stack=[]
for i in range(len(s)):
	if s[i] in "+-*":
		q1=stack.pop()
		q2=stack.pop() 
		if s[i]=="+":
			stack.append(q1+q2)
		elif s[i]=="-":
			stack.append(q2-q1)
		else:
			stack.append(q1*q2)
	else:
		stack.append(int(s[i]))
print(*stack)
