Подсчитать количество запятых в заданном тексте — QBasic(Бейсик)

CLS
LINE INPUT "vvedite text: "; t$
FOR i = 1 TO LEN(t$)
    IF MID$(t$, i, 1) = "," THEN k = k + 1
NEXT
PRINT k

INPUT "FILE NAME "; F$
OPEN F$ FOR INPUT AS #1
DO
    Q = 0
    LINE INPUT #1, T$
    DO
        Q = INSTR(Q + 1, T$, ",")
        IF Q > 0 THEN N = N + 1 ELSE EXIT DO
    LOOP
LOOP UNTIL EOF(1)
PRINT N