Произведение всех элементов i-ой строки и j-того столбца (j,i- вводятся с клавиатуры; I,j <= n ). Матрица A (n,n) - QBasic(Бейсик)

INPUT "vvedite kolichestvo strok i stolbcov N ", n
DIM a(n, n)
FOR i = 1 TO n
    FOR j = 1 TO n
        INPUT "vvedite element ", a(i, j)
    NEXT
NEXT
PRINT "matrica "
FOR i = 1 TO n
    FOR j = 1 TO n
        PRINT n(i, j);
    NEXT
    PRINT
NEXT
INPUT "vvedite nomer stroki ", s
INPUT "vvedite nomer stolnca ", b
ps = 1
pb = 1
FOR i = 1 TO n
    pb = pb * a(i, b)
    ps = ps * a(s, i)
NEXT
PRINT "proizvedenie elementov "; b; " stolbca="; pb
PRINT "proizvedenie elementov "; s; " stroki="; ps