Separating a part of the string from it's three first characters

[apace]

I am trying to separate a string from it's three initial characters.

Example:

100345-123-2455

100

345-123-2455

345-123-544444

345

123-544444

I have figured out, with help, how to separate the three characters, using the function: =IF(COUNTIF($J$2:$J$100;LEFT(A2;3)&"*")>0;LEFT(A2;3);"Missing").

I am now struggling with separating the other part of the string. Sometimes the string occurs with a dash after the first three character, sometimes without it, and I am confused as to how to write a function that would understand that.

 

[taurean]

Second portion can be extracted by introducing a test for 4th character like below:

=MID(A2,IF(MID(A2,4,1)="-",5,4),LEN(A2))

 

[apace]

Second portion can be extracted by introducing a test for 4th character like below:

=MID(A2,IF(MID(A2,4,1)="-",5,4),LEN(A2))

oh wow, that's really smart, didn't even think about that. I initially just separated by creating a function that recognized the first dash. Thank you so much!