var
a,b,c,d,e,f,t,o,m:longint;
cn,d1,d2:array[0..1000]of longint;
procedure dfs (x,y,z:longint);
var
g,h,q,e:longint;
begin
if (x=0)and(y=0) then
if o<z-1 then
o:=z-1;
for g:=1 to m do
begin
if x<>0 then
if cn[g]=x then
dfs(d1[g],d2[g],z+1);
if y<>0 then
if cn[g]=y then
dfs(d1[g],d2[g],z+1);
end;




end;
begin
assign(input,'stroll.in');
assign(output,'stroll.out');
reset(input);
rewrite(output);
read(m);
for a:=1 to m-1 do
begin
read(cn[a],d1[a],d2[a]);
readln;
end;
for a:=1 to m do
if cn[a]=1 then
dfs(d1[a],d2[a],0);
write(o+2);
close(input);
close(output);
end.