Caesar Cipher (+3 letters left)

Enter your text in the field below, press the button — and get the encrypted version.
Please use only latin alphabit

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Secured text

P.S.: I did this task already at Secret Shift Value task. But Springboard asking me to do it again and use "for" while I already use it. In comments I should explain using % alphabet.length. That was also done earlier.I'll give comment again: //here we use letters that are close to end of alphabit and need to run alphabet from the beginning