#include <stdio.h>
#define DIMT 1000005
#define DIMN 50010
struct intrv {int x,y,c;} a[DIMN];
int min[DIMT];
int n,t,rez;
void read ()
{
    int i;
    scanf ("%d%d",&n,&t);
    for (i=1; i<=n; ++i)
        scanf ("%d%d%d",&a[i].x,&a[i].y,&a[i].c);
}
void solve ()
{
    int i,j;
    for (i=1; i<=n; ++i)
        for (j=a[i].x; j<=a[i].y; ++j)
			if (a[i].c<min[j] || min[j]==0)
				min[j]=a[i].c;
    for (i=1; i<=t; ++i)
        rez+=min[i];
    printf ("%d",rez);
}
int main ()
{
    freopen ("gardieni.in","r",stdin);
    freopen ("gardieni.out","w",stdout);
    read ();
    solve ();
    return 0;
}