program officer(input,output);
var
 n,o:longint;
 a:array[1..10000]of longint;
 f:array[1..10000]of boolean;
 p:array[1..10000]of longint;
 head,i,j,ans:longint;
 flag:boolean;

procedure dg(x,y,z:longint);
begin
 if y=x then
 begin
  inc(head);
  p[head]:=z;
 end
 else
 begin
  f[y]:=true;
  dg(x,a[y],z+1);
 end;
end;

function pro(x,y:longint):longint;
var
 g:longint;
begin
 if y>x then
 begin
  g:=y;
  y:=x;
  x:=g;
 end;
 if x mod y=0 then o:=y
 else
 begin
  pro(y,x mod y);
 end;
end;

begin
 assign(input,'officer.in');
 reset(input);
 readln(n);
 for i:=1 to n do readln(a[i]);
 close(input);

 for i:=1 to n do
  if f[i]=false then
  begin
   f[i]:=true;
   dg(i,a[i],1);
  end;

 ans:=1;
 for i:=1 to head do
 begin
  o:=0;
  pro(ans,p[i]);
  ans:=(ans*p[i]) div o;
 end;

 assign(output,'officer.out');
 rewrite(output);
 writeln(ans);
 close(output);
end.