program sled;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
  n, i, j, k, met: integer;
  a, vat: array[1..110] of integer;
begin
  met := 0;
  read(n, k);
  for i := 1 to k do
    read(a[i]);
  a[k + 1] := n + 1;
  for i := k + 1 downto 2 do
    if (abs(a[i] - a[i - 1]) > 1) then begin
      inc(a[i - 1]);
      inc(met);
      for j := i to k do
        a[j] := a[j - 1] + 1;
      break;
    end;
  if (met <> 0) then
    for i := 1 to k do
      write(a[i],' ')
  else write(0);
end.