9 есть ли в строке подходящие пары

a = [[1, 2, 3, 4, 5], [7, 8, 9, 10, 11]]
cnt = 0
for e in a:
    f = False
    for i in range(5):
        b = e.copy()
        b.pop(i)
        if (b[0] + b[1]) / 2 == (b[2] + b[3]) / 2 == e[i]:
            f = True
        if (b[0] + b[2]) / 2 == (b[1] + b[3]) / 2 == e[i]:
            f = True
        if (b[0] + b[3]) / 2 == (b[1] + b[2]) / 2 == e[i]:
            f = True
    if f:
        cnt += 1
print(cnt)