program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils;
type
ss = string[35];
TTree = ^Tree;
Tree  = record
         k:ss;
         l:longint;
         next:TTree;
        end;
var
g:ss;
n,d,i :longint;
f:array[0..111111] of TTree;

function hash(x:ss):longint;
var t,j:longint;
begin
t:=0;
 for j:=1 to length(x) do
  inc(t , j * 8 * ( ord(x[j]) - 96 ) );
hash:=t;
end;

function count(x:ss;y:longint):longint;
var t:TTree;
begin
t:=f[y];
 while t <> nil do
  begin
   if t^.k = x then
    begin
     count:=t^.l;
     inc(t^.l);
     exit;
    end;
   t:=t^.next;
  end;
 count:=0;
end;

function get(x:ss):longint;
var t,ans:longint;b:TTree;
begin
 t:=hash(x);
 ans:=count(x,t);
  if ans = 0 then
   begin
    New(b);
    b^.next:=f[t];
    f[t]:=b;
    b^.k:=x;
    b^.l:=1;
   end;
 get:=ans;
end;

begin
Readln(n);
 for i:=1 to n do
  begin
   Readln(g);
    d:=get(g);
    if d = 0 then Writeln('OK')
    else Writeln(g,d);
  end;
end.