27 (макс сумма не кратная k)

#https://inf-ege.sdamgia.ru/problem?id=27424
data = open('27-B_demo.txt').readlines()
n = int(data[0])
sum = 0
for i in range(1, n + 1):
    x, y = map(int, data[i].split())
    sum += max(x, y)
if (sum % 3) != 0:
    print(sum)
    exit(0)
mn = 100000000000
for i in range(1, n + 1):
    x, y = map(int, data[i].split())
    if (abs(x - y) % 3) != 0: #max(x, y) - min(x, y)
        mn = min(mn, abs(x - y))
print(sum - mn)