Program gardieni;
var a:array[1..1000001] of longint;
    n,t,c:longint;
    x,b,i,j:longint;
    f,q:text;
begin
assign(f,'gardieni.in');
reset(f);
assign(q,'gardieni.out');
rewrite(q);
read(f,n,t);
for i:=1 to n do
begin
        read(f,x,b,c);
        for j:=x to b do if (a[j]>c) or (a[j]=0) then a[j]:=c;
end;
n:=0;
for i:=1 to t do n:=n+a[i];
write(q,n);
close(f);
close(q);
end.