# 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])
# print(res)
from itertools import count


f = open('24_7.txt').read()
a=[]
j=0
count = 0
for i in range(len(f)-1):
    if f[i]+f[i+1]=='CD':
        count+=1
        if count>160:
            count=1
            a.append(i+1-j)
            j=i
print(max(a))