var
  i,c,n:longint;
  total:int64;
  a,f:array[0..20000]of longint;
  ans:array[0..20000]of int64;

function gcd(x,y:int64):int64;
begin
  if y=0 then gcd:=x
  else gcd:=gcd(y,x mod y);
end;

procedure go(k:longint);
begin
  if (total>0)and(k=i) then exit;
  total:=total+1;
  go(a[k]);
end;

begin
  assign(input,'officer.in'); reset(input);
  assign(output,'officer.out'); rewrite(output);
  readln(n);
  for i:=1 to n do read(a[i]);
  for i:=1 to n do
  begin
    total:=0;
    go(i);
    f[i]:=total;
  end;
  ans[1]:=f[1];
  for i:=2 to n do
  begin
    c:=gcd(ans[i-1],f[i]);
    ans[i]:=(ans[i-1]*f[i]) div c;
  end;
  writeln(ans[n]);
  close(input);
  close(output);
end.