s = 'ABFDFDFDSTFDFDFDFDTSFDFDFDFSDFDFFD'
f = [1] * len(s)
for i in range(1, len(s)):
    if (s[i-1] == 'S' and s[i] == 'T') or (s[i-1] == 'T' and s[i] == 'S'):
        f[i] = 0
        f[i-1] = 0
    else:
        f[i] = f[i-1] + 1
    if f[i] == 13:
        print(s[i-13:i+1])
print(max(f))