#/usr/bin/env python


cal_cur = 0
cal_all = []

with open("input.txt", "r") as f:
    for line in f:
        try:
            cal = int(line)
        except ValueError:
            cal_all.append(cal_cur)
            cal_cur = 0
            continue
        cal_cur += cal

print(sum(sorted(cal_all, reverse=True)[:3]))