cur_cal = 0
max_cal = 0
with open("input", encoding="utf-8") as f:
    foods = f.readlines()
for food in foods:
    if food == "\n":
        if cur_cal > max_cal:
            max_cal = cur_cal
        cur_cal = 0
    else:
        cur_cal += int(food)
print(f"highest calories is {max_cal}")