program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils;

type
  TElem = record
    letter: char;
    next: array['a'..'z'] of longint;
    cnt: longint;
    terminal: boolean;
  end;
var
  cnt, free, i, n: longint;
  bor: array[1..5000000] of TElem;
  st: string;

function cn_term(st: string): longint;
var
  cur: longint;
  i: longint;
begin
  cur:= 1;
  for i:= 1 to length(st) do begin
    if bor[cur].next[st[i]] <> 0 then begin
      cur:= bor[cur].next[st[i]];
    end else begin
      inc(free);
      bor[cur].next[st[i]]:= free;
      cur:= bor[cur].next[st[i]];
    end;
  end;

  bor[cur].terminal:= true;
  inc(bor[cur].cnt);
  result:= bor[cur].cnt;

end;

begin                             {
  reset(input,'input.txt');
  rewrite(output,'output.txt');  }

  readln(n);
  free:= 0;
  for i:= 1 to n do begin
    readln(st);
    cnt:= cn_term(st);
    if cnt = 1 then writeln('OK') else begin
      st:= st + inttostr(cnt);
      writeln(st);
    end;
  end;

end.