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
expressions = raw_input( ).split( " " )
stack = []
for op in expressions:
	if "+" == op:
		b = stack.pop( )
		a = stack.pop( )
		stack.append( a + b )
	elif "-" == op:
		b = stack.pop( )
		a = stack.pop( )
		stack.append( a - b	)
	elif "*" == op:
		b = stack.pop( )
		a = stack.pop( )
		stack.append( a * b )
	else:
		stack.append( int( op ) )
print( stack.pop( ) )