# import re
#
# with open('24_7.txt', 'r') as file:
#     data = file.readline()
#
# data = re.sub('CD', '--', data)
#
# not_CD = r'(-?[^-]*)'
#
# CD_and_any = r'(?:--[^-]*){160}-?'
# la_CD_group = rf'(?=({CD_and_any}))'
#
# pattern = rf'{not_CD}{la_CD_group}'
#
# matches = re.findall(pattern, data)
#
# res = max([len(match[0] + match[1])
#            for match in matches])


f = open('24_7.txt').read().strip()
a = []
for i in range(len(f) - 1):
    if f[i]+f[i+1] == 'CD':
        a.append(i)
print(max([p1-p for p,p1 in zip(a, a[161:])]))

# lst1 = [0, 1, 2, 3, 4, 5]
# lst2 = [5, 3, 2, 0, 4, 1]
# lst3 = ['нуль', 'один', 'два', 'три', 'четыре', 'пять']
# for a, b, c in zip(lst1, lst2, lst3):
#     print(f'{c} {a} {b}')