var
   N, N1, N2, z, a, x, y, i: integer;
   m, h: real;

begin
   for N := 1000 to 9999 do
   begin
      x := N div 1000;
      N1 := N mod 1000;
      y := N1 div 100;
      N2 := N1 mod 100;
      z := N2 mod 10;
      a := N2 div 10;
      if (x = y) and (z = a) then
      begin
         m := sqrt(N);
         if trunc(m) = m then
         begin
            writeln(N);
         end
         else
         begin
            break;
         end;
      end
      else
      begin
         break;
      end;
   end;
   readln;
end.