---

file = open('numbers.txt')
data = [int(x) for x in file]
res = []
for i in range(len(data) - 1):
    if data[i] % 2 == 0 \
    and data[i + 1] % 2 == 0:
        res.append(data[i] + data[i + 1])
print(max(res))