How to get the chen letter

1/Go to Féli-Cité and enter the television building.
2/Go to the 2nd floor and talk to the man next to a blonde girl.
3/He will ask you to give him your opinion on television.
4/Answer him "All" "Together".
5/Then "Connection" "Wi-Fi".
6/He will then give you a mystery gift which is the Shaymin Nintendo event.
7/Save and then turn off your console.
8/Go to the "Mystery Gift" option on the main screen of the game.
9/Choose "Receive gift" then "Wi-Fi Connection".
10/You will receive Professor Chen's letter to go to the end of Route 224.
11/Return to Route 224 and Professor Chen will be waiting for you next to the smooth stone at the end.
12/He will ask you to thank someone to pass the stone. Then thank "Chen".
13/You will see a field of flowers but also Shaymin.
14/Go to the back of the flower field and you will find Shaymin.
15/You will battle it, but do not knock it out as it is unique.
16/Put it to sleep and capture it several times with Ultra Balls or Honor Balls (I didn't put it to sleep, I threw a lot of Honor Balls when it was weak).