This solution comes from Andrei from School No. 205,
Bucharest, Romania.

To solve this problem I followed the following steps:

- associating to the letters of the alphabet numbers between 0
and 25, I transformed the coded message into a set of pairs of
numbers $(\alpha',\beta')$

- I solved the system of equations for $(\alpha,\beta)$ in
terms of $(\alpha',\beta')$.

- I used the same association as in the first step, and I
transformed the set of numbers $(\alpha, \beta)$ into letters, and
I found the message.

a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z |

0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 |

For each pair of numbers $(\alpha', \beta')$ I have to solve
the system to determine $(\alpha, \beta)$ $$ \alpha'= \alpha +
3\beta\pmod {26}\quad (1) $$ $$\beta' = 5\beta \quad \pmod{26}\quad
(2)$$

I start from the last equation: $$\beta = {1\over 5}\beta'
\pmod{26}$$ To determine 1/5 (mod 26), I first constructed the
table of multiplication for 5 (mod 26) to see where I obtain 1. As
21 multiplied by 5 gives 1 (mod 26) it follows that 1/5 (mod 26) is
21. This means: $$\beta = 21\beta' \pmod{26}\quad (3)$$ and for
$\alpha$ I obtained successively $$\alpha = \alpha'-3\beta =
\alpha'-3\times 21\beta' = \alpha' - 11\beta' \pmod{26} $$ that is
$$\alpha = \alpha' +15\beta' \pmod{26} \quad (4).$$ Now, the
sequence of numbers $(\alpha', \beta')$ is transformed by equations
(3) and (4) into the sequence $(\alpha,\beta)$

$C$ | $\alpha'$ | $\beta'$ | $\alpha$ | $\beta$ | $P$ |

dj | 3 | 9 | 8 | 7 | ih |

lb | 11 | 1 | 0 | 21 | av |

rn | 17 | 13 | 4 | 13 | en |

qm | 16 | 12 | 14 | 18 | os |

bu | 1 | 20 | 15 | 4 | pe |

ao | 0 | 14 | 2 | 8 | gi |

hd | 7 | 3 | 0 | 11 | al |

eo | 4 | 14 | 6 | 8 | gi |

kr | 10 | 17 | 5 | 19 | ft |

ia | 8 | 0 | 8 | 0 | ia |

cs | 2 | 18 | 12 | 14 | mo |

ud | 20 | 3 | 13 | 11 | nl |

rx | 17 | 23 | 24 | 15 | yp |

cm | 2 | 12 | 0 | 18 | as |

qo | 16 | 14 | 18 | 8 | si |

bn | 1 | 13 | 14 | 13 | on |

fr | 5 | 17 | 0 | 19 | at |

ld | 11 | 3 | 4 | 11 | el |

ek | 4 | 10 | 24 | 2 | yc |

th | 19 | 7 | 20 | 17 | ur |

ys | 24 | 18 | 8 | 14 | io |

wm | 22 | 12 | 20 | 18 | us |

The message could be read as the quotation from Einstein
talking about himself as a mathematician:'I have no special gift. I
am only passionately curious'.