FUNCTION L (X)
    L = LOG(X) / LOG(2)
END FUNCTION

S$ = "1223334444"
U$ = ""
FOR I = 1 TO LEN(S$)
    K = 0
    FOR J = 1 TO LEN(U$)
        IF MID$(U$, J, 1) = MID$(S$, I, 1) THEN K = 1
    NEXT J
    IF K = 0 THEN U$ = U$ + MID$(S$, I, 1)
NEXT I
DIM R(LEN(U$) - 1)
FOR I = 1 TO LEN(U$)
    C = 0
    FOR J = 1 TO LEN(S$)
        IF MID$(U$, I, 1) = MID$(S$, J, 1) THEN C = C + 1
    NEXT J
    R(I - 1) = (C / LEN(S$)) * L(C / LEN(S$))
NEXT I
E = 0
FOR I = 0 TO LEN(U$) - 1
    E = E - R(I)
NEXT I
PRINT E
END