type vicotre_stie_vecotri=record
                a,b,c:longint;
                end;
var v:array[1..50100] of vicotre_stie_vecotri;
    i,j,n,t,s:longint;
    x:array[1..1000100] of longint;

begin
assign(input,'gardieni.in');reset(input);
assign(output,'gardieni.out');rewrite(output);
readln(n,t);
for i:=1 to n do
        readln(v[i].a,v[i].b,v[i].c);
for i:=1 to t do
        x[i]:=maxlongint;
for i:=1 to n do
        for j:=v[i].a to v[i].b do
                if (x[j]>v[i].c) then
                        x[j]:=v[i].c;
for i:=1 to t do
        s:=s+x[i];
writeln(s);
close(input);close(output);
end.