Задача 5

ar_count = 2
ge_count = 2
max_ar_count = 2
max_ge_count = 2

prev_elem = int(input())
inp = int(input())
d = inp - prev_elem
q = inp / prev_elem
while True:
    prev_elem = inp
    inp = int(input())
    if inp == 0:
        if ar_count > max_ar_count:
            max_ar_count = ar_count
        if ge_count > max_ge_count:
            max_ge_count = ge_count
        break

    if inp - prev_elem == d:
        ar_count += 1
    else:
        if ar_count > max_ar_count:
            max_ar_count = ar_count
        ar_count = 2
        d = inp - prev_elem

    if inp / prev_elem == q:
        ge_count += 1
    else:
        if ge_count > max_ge_count:
            max_ge_count = ge_count
        ge_count = 2
        q = inp / prev_elem

print(max(max_ar_count, max_ge_count))