num = input() # Reading input

count = 0
count_list = []  # To store count

for i in range(len(num)):
    if (num[i] == 1):
    {
        count += 1
        if (num[i + 1] == 0)
        {
            count_list.append(count)
            count = 0
         }
    }

print("Max number of consecutive 1's is:", max(count_list))