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
exp = input().split()

s = []
tmp = 0

for x in exp:
	if x == '+':
		tmp = int(s.pop()) + int(s.pop())
		s.append(tmp)
	elif x == '-':
		tmp = -1 * (int(s.pop()) - int(s.pop()))
		s.append(tmp)
	elif x == '*':
		tmp = int(s.pop()) * int(s.pop())
		s.append(tmp)
	else:
		s.append(int(x))

print(tmp)