Qbasic to find positive, negative or neutral using Sub

DECLARE SUB CHECK(N)
CLS
INPUT "Enter any number.";N
CALL CHECK(N)
END

SUB CHECK(N)
IF N > 0  THEN
PRINT "The number is positive"
ELSEIF N < 0 THEN
PRINT"The number is negative"
ELSE
PRINT "The number is neutral"
END IF
END SUB