#!/usr/bin/env python

elves = []

with open('input') as f:
    elf = []
    for line in f:
        if line == "\n":
            elves.append(elf)
            elf = []
        else:
            calories = int(line)
            elf.append(calories)

print(sum(sorted(map(sum, elves), reverse=True)[0:3]))