LET 	s = 0
	LET 	i = 1
	VAR 	n
	READ
	POP 	n
test :
	PUSH 	i
	PUSH 	n
	JE 	fin
	PUSH	i
	PUSH	s
	ADD
	POP	s
	PUSH	i
	VAL	1
	ADD
	POP	i
	JMP     test
fin :
	PUSH	s
	WRITE
	HALT