QBASIC to find Avearge of three number using FUNCTION

DECLARE FUNCTION AVG ( A, B, C)
CLS
INPUT " Enter any three number"; A, B, C
PRINT " Average of three number"; AVG ( A, B, C)
END

FUNCTION AVG ( A, B, C)
AV = ( A + B + C ) / 3
AVG = AV
END FUNCTION