Program hrt;
uses crt;
label lab1;
type TPot=record
     b,e,max,now:integer;
     end;
var sum,now:array[0..100,0..100]of integer;
    a:array[0..100]of TPot;
{    pot:array[0..10000]of Tpot;
}    i,j,n,b,e,m,c,mmm,kk,mm,lll:integer;
begin
clrscr;
assign(input,'HOMEBREW.DAT');
{assign(output,'HOMEBREW.RES');
}reset(input);
read(n);
mm:=0;
while not(EOF(input)) do
begin
readln(b,e,m);
if e=n+1 then inc(mm);
sum[b,e]:=m;
end;
for i:=0 to n do
 begin
 for j:=1 to n+1 do
 write(sum[i,j],' ');
 writeln;
 end;
c:=-1;
kk:=0;
i:=0;
lll:=-1;

{for i:=0 to n+1 do}
while lll<0 do
 begin
  a[i].b:=i;
lab1: for j:=0 to n+1 do
   if (sum[i,j]>0)and(j>c) then
    begin
    c:=j;
    Break;
    end
    else if j=n+1 then c:=-1;
  a[i].e:=c;
  a[i].max:=sum[i,j];
  if a[i].max>a[i].now then
  inc(a[i].now) else goto lab1;
  i:=j;
  inc(mmm);
  if i=n+1 then
  begin
  i:=0;
  inc(kk);
  end;
  if mm=kk then lll:=1;
  end;
writeln(mmm);
close(input);
repeat until keypressed;
end.