var pr:array[1..50050] of int64;
    n,i,j:longint;
    c,su,a,b,t:int64;
    f,g:text;
begin
assign(f,'gardieni.in');reset(f);
assign(g,'gardieni.out');rewrite(g);
read(f,n,t);
for i:=1 to n do
 begin
   read(f,a,b,c);
   for j:=a to b do
      if (pr[j]=0) or (pr[j]>c) then pr[j]:=c;
  end;
 su:=0;
 for i:=1 to t do
    su:=su+pr[i];
 write(g,su);
 close(f);close(g);
 end.