N24_sample

f = open('24.txt')
s = f.readline()
f.close()
s = s.replace('O', 'A')
s = s.replace('D', 'C')
s = s.replace('F', 'C')
k = 0
t = ''
for i in range(1000):
    t = 'CA' * i
    if t in s:
        k = max(k, i)
print(k)