Let's Hack

We are hacker! You analyze the password hidden from letters , and break firewall.
Let the hacking begin!

+++++How to play+++++
Input the password to break through firewall.

they want you to find the letters that appear only once on the board. It doesn't matter what order you find them in.

For example,
If letter is "g g a g g g b g c d g g e" then the password is ' a ' , ' b ' , ' c ' , ' d ' , ' e ' .
It can input in any order. ("abcde", "bcaed", "dacbe", ....)

Firewall is 5 layers. Compete the time to break through it.
Enjoy!