def main():
    s = input("Input a string: ")
    i = 0
    j = len(s) - 1

    ok = True
    while i < j:
        if s[i] != s[j]:
            ok = False
            break
        i += 1
        j -= 1

    if ok:
        print("PALINDROME")
    else:
        print("NOT A PALINDROME")


if __name__ == "__main__":
    main()