Seven days a week, of the seven words, only Wednesday is nine letters, which is consistent with the length of NADKARDOB given in the title. Comparing these two words, we can see that the letter S in the original text should correspond to the letter R; The letter e of the original text, the corresponding password should be the letter a; The letter n in the original text, the corresponding password should be the letter K; The original letter d, the corresponding password should be the letter d, therefore, the word SEND should be expressed as RAKD with the same password.