extract a particular number

[houdinix64]

hi please help me, i want to extract a particular number (mobile network prefix only) and saved it to a certain variable..

example: from this mobile number +639195555777,all i needed is +63919 and saved it to a variable. i have no idea,please help me..sorry for my bad english..peace ✌

edit.. problem solved after searching entire from the forum.

{left(sms_sender, 6)}