var
  p,l1,l2,i,t,n,time:longint;
  v:boolean;
  s1,s2:string;

begin
  assign(input,'dna.in'); reset(input);
  assign(output,'dna.out'); rewrite(output);
  readln(time);
  randomize;
  for t:=1 to time do
  begin
    readln(s1);
    readln(s2);
    l1:=length(s1);
    l2:=length(s2);
    p:=0;
    v:=true;
    for i:=1 to l2 do
    begin
      if pos(s2[i],s1)>=p then p:=pos(s2[i],s1)
      else begin
        writeln(-1);
        v:=false;
	    break;
      end;
    end;  
    if not v then continue;
    writeln(random(2*l2));
  end;
  close(input);
  close(output);
end.