txt = "NTCGPDOPANFLHJINTOOFITOVJHJCTMMHIHEMTCPFDWTSOFSHTOGFWTETTJJTBTOOFSZOVEOCHCVCHPJHOCGTOHNQMTOCNTCGPDCGFCSTQMFBTOFBGFSFBCTSHJCGTQMFHJCTYCXHCGFAHYTDDHAATSTJCBGFSFBCTSHJCGTBHQGTSCTYCCGHONTCGPDQSTOTSWTOCGTMTCCTSASTRVTJBZHJCGTQMFHJCTYCFJDOPPJTBFJOTFSBGAPSCGTQMFHJCTYCASPNFIHWTJBHQGTSCTYCEZBPNQFSHJICGTASTRVTJBZPATFBGMTCCTSFIFHJOCCGTLJPXJBPNNPJASTRVTJBZHJCGTVJDTSMZHJIMFJIVFIT"

freq_tab = ["E", "T", "A", "I", "N", "O", "S", "R", "L", "D", "H", "C", "U", "M", "F", "P", "Y", "G", "W", "V", "B",
            "K", "X", "J", "Q", "Z"]


def freq_letter(txt):
    dic = {}
    for letter in txt:
        if letter in dic:
            dic[letter] += 1
        else:
            dic[letter] = 1
    return dict(sorted(dic.items(), key=lambda item: item[1]))


def freq_m_letter(txt, nbr=2):
    dic = {}
    i = 0
    while i < len(txt) - 1:
        letter = txt[i:i + nbr]
        if letter in dic:
            dic[letter] += 1
        else:
            dic[letter] = 1
        i += 1
    return dict(sorted(filter(lambda x: x[1] > 2, dic.items()), key=lambda item: item[1]))


def trad(txt_, replace_):
    sol = ""
    for letter in txt_:
        if letter in replace_:
            sol += replace_[letter]
        else:
            sol += letter
    return sol


if __name__ == '__main__':
    replace = {"C": "t",
               "G": "h",
               "T": "e",
               "H": "i",
               "J": "n",
               "S": "r",
               "F": "a",
               "Y": "x",
               "B": "c",
               "I": "g",
               "M": "l",
               "Q": "p",
               "V": "u",
               "A": "f",
               "R": "q",
               "Z": "y",
               "D": "d",
               "P": "o",
               "O": "s",
               "N": "m",
               "L": "k",
               "E": "b",
               "W": "v",
               "X": "w"
               }

    freq = freq_letter(txt)
    print(freq)
    for i in range(2, 10):
        print("===")
        freq_2 = freq_m_letter(txt, i)
        print(freq_2)
        print('{', end=" ")
        for a in freq_2:
            print(trad(a, replace), end=', ')
        print('}')

    sol = trad(txt, replace)

    print('====')
    print(sol)