17 для любых пар элементов

ch = [int(x) for x in open('17.txt')]


def summa_kra_8(x, y):
    if (x + y) % 8 == 0:
        return 1
    else:
        return 0


count = max_sum = 0
for i in range(0, len(ch)-1):
    for a in range(i+1, len(ch)):
        if summa_kra_8(ch[i], ch[a]):
            count += 1
            max_sum = max(max_sum, ch[i]+ch[a])

print(count, max_sum)