with open('input') as f:
    groups = []
    sum_ = 0
    for line in f:
        line = line.strip()
        if line == '':
            if sum_ > 0:
                groups.append(sum_)
            sum_ = 0
        else:
            sum_ += int(line)

    a = max(groups)
    groups.remove(max(groups))
    b = max(groups)
    groups.remove(max(groups))
    c = max(groups)
    groups.remove(max(groups))

    print(a + b + c)