task 24

f = open(r'C:\Users\thisp\Desktop\24.txt')
max_seq = 0
curr_seq = 0
for line in f:
    for i in range(1,len(line)):
        if line[i] == 'Y' or line[i] == 'Z':
            if line[i-1] == 'X':
                max_seq = max(max_seq,curr_seq)
                curr_seq = 0
        else:
            curr_seq += 1
print(max_seq)