program df;
var
f1,f2:text;
s:array[1..10000]of string;
f:array[1..10000]of string;
s1:string;
p,ans,n,i,j,k:integer;
begin
assign(f1,'link.in');
assign(f2,'link.out');
reset(f1);
rewrite(f2);
readln(f1,n);
 for i:= 1 to n do readln(f1,s[i]);
f[1]:=s[1];p:=1;
for i:= 2 to n do begin
       s1:=copy(s[i],1,length(f[p]));
       if s1=f[p] then begin
                  inc(p);
                   if ans<p then ans:=p;
                      f[p]:=s[i];
                       end
                  else begin
                for j:=p downto 1 do begin
                  s1:=copy(s[i],1,length(f[j-1]));
                  if s1=f[j-1]then begin f[j]:=s[i];p:=j;break;end;
                  if j=2 then begin f[1]:=s[i];p:=1;end;
                                        end;
                        end;
       end;
writeln(f2,ans);
close(f1);
close(f2);
end.