=MID(B2,FIND(".",SUBSTITUTE(B2,".",0,1))+1,FIND(".",SUBSTITUTE(SUBSTITUTE(B2,".",0,1),".",0,1))-FIND(".",SUBSTITUTE(B2,".",0,1))-1)
=MID(A2,FIND("@",SUBSTITUTE(A2,".","@",2))+1,FIND("@",SUBSTITUTE(A2,".","@",3))-FIND("@",SUBSTITUTE(A2,".","@",2))-1)