def is_cpctf_like(sub):
    return (
        len(sub) == 5 and
        sub[0] == sub[2] and
        len(set([sub[0], sub[1], sub[3], sub[4]])) == 4
    )

def count_cpctf_like(s):
    n = len(s)
    count = 0
    for i in range(n - 4):
        if is_cpctf_like(s[i:i+5]):
            count += 1
    return count

# Sample inputs
print(count_cpctf_like("NEOSHOWCASE"))         # Output: 16
print(count_cpctf_like("PPC"))                 # Output: 0
print(count_cpctf_like("CPCTFCPCTFCPCTFCPCTFCPCTFCPCTF"))  # Output: 4011