В каждой строке матрицы А(n,m) максимальный элемент заменить на полусумму первого и последнего отрицательного в строке- QBasic(Бейсик)

CLS
INPUT "vv. kol-vo strok ", n
INPUT "vv. kol-vo stolbcov ", m
DIM a(n, m)
RANDOMIZE TIMER
FOR i = 1 TO n
    FOR j = 1 TO m
        a(i, j) = INT(RND * 20) - 10
    NEXT
NEXT
PRINT "massiv"
FOR i = 1 TO n
    FOR j = 1 TO m
        PRINT a(i, j); " ";
    NEXT
    PRINT
NEXT

FOR i = 1 TO n
    f = 0
    max = a(i, 1)
    nom = 1
    FOR j = 1 TO m
        IF a(i, j) > max THEN max = a(i, j): nom = j
        IF a(i, j) < 0 THEN nom1 = j: f = 1
    NEXT
    FOR k = m TO 1 STEP -1
        IF a(i, k) < 0 THEN nom2 = k: IF f = 1 THEN f = 2
    NEXT
    IF f = 2 THEN a(i, nom) = (a(i, nom1) + a(i, nom2)) / 2
NEXT

PRINT "novyj massiv"
FOR i = 1 TO n
    FOR j = 1 TO m
        PRINT a(i, j); " ";
    NEXT
    PRINT
NEXT