#/usr/bin/env python

cal_max = 0
cal_cur = 0

with open("input.txt", "r") as f:
    for line in f:

        try:
            cal = int(line)
        except ValueError:
            cal_max = max(cal_cur, cal_max)
            cal_cur = 0
            continue
        cal_cur += cal

print(cal_max)