type
  answer=record
    range_from,range_to:longint;
    parity:boolean;
end;

var answers:array[1..5000] of answer;

procedure exchange(p,q:word);
var r:answer;
 begin
  r:=answers[p];
  answers[p]:=answers[q];
  answers[q]:=r
 end;

var contradiction:boolean;
    length:longint;
    answers_given:word;
    answers_read:word;
    answers_stored:word;
    i:word;
    s:string;
begin
 readln(length);
 readln(answers_given);
 contradiction:=false;
 answers_read:=0; answers_stored:=0;
 if answers_given<>0 then
   repeat
     inc(answers_read);
     inc(answers_stored);
     readln(answers[answers_stored].range_from,answers
[answers_stored].range_to,s);
     answers[answers_stored].parity:=s=' odd';
     i:=answers_stored-1;
     while (i>0) and (answers[i].range_from>=answers
[answers_stored].range_from) do
       dec(i);
     inc(i);
     while (i<>answers_stored) and (answers[i].range_from=answers
[answers_stored].range_from) do
       begin
         if answers[i].range_to>answers[answers_stored].range_to then
           exchange(i,answers_stored);
         if answers[i].range_to=answers[answers_stored].range_to then
           begin
             contradiction:=answers[i].parity<>answers
[answers_stored].parity;
             dec(answers_stored);
             i:=answers_stored;
           end
         else
           begin
             answers[answers_stored].range_from:=answers
[i].range_to+1;
             answers[answers_stored].parity:=answers[i].parity xor
answers[answers_stored].parity;
           end;
         while (i<answers_stored) and (answers[i].range_from<answers
[answers_stored].range_from) do
           inc(i);
       end;
    while (i<>answers_stored) do
      begin
        exchange(i,answers_stored);
        inc(i)
      end
   until contradiction or (answers_read=answers_given);
 {Writing results to the output file}
 if contradiction then
   writeln(answers_read-1)
 else
   writeln(answers_read);
end.