Program heapuri;
 var f,g:text; a:array[1..10]of boolean;
     b:array[1..10]of longint;
     k,n:longint;
 procedure calcul;
  var x,z,w:longint; y:1..3;
  begin
   for x:=1 to n do begin
     read (f,y);
     case y of
       1: begin
            readln (f,z);
            k:=k+1;
            b[k]:=z;
            a[z]:=true;
          end;
       2: begin
            readln (f,z);
            a[b[z]]:=false;
          end;
       3: begin
           w:=1;
           while not a[w] do w:=w+1;
           writeln (g,w);
           readln (f);
          end;
     end;
   end;
  end;
 begin
  assign (f,'heapuri.in'); reset (f);
  assign (g,'heapuri.out'); rewrite (g);
  readln (f,n);
  k:=0;
  calcul;
  close (f); close (g);
 end.