#include<stdio.h>
#include<algorithm>
using namespace std;

#define INF 3000000

struct gard {int x,y,c;}v[60000];
int j,n,t,i,c[1000011];

int cmp(gard a, gard b){
return a.x<b.x;
}


int main(){


FILE *f=fopen("gardieni.in","r");
fscanf(f,"%d %d",&n,&t);

  for(i=1;i<=n;i++){
  fscanf(f,"%d %d %d",&v[i].x,&v[i].y,&v[i].c);
  }

fclose(f);

//sort(v+1,v+n+1,cmp);

  for(i=1;i<=t;i++){
  c[i]=INF;
  }


  for(i=1;i<=n;i++){

    for(j=v[i].x;j<=v[i].y;j++)
     if(c[j]>v[i].c)
     c[j]=v[i].c;

  }

  

long long cost=0;

  for(i=1;i<=t;i++)
  cost+=(long long)c[i];


FILE *g=fopen("gardieni.out","w");
fprintf(g,"%lld",cost);
fclose(g);

return 0;
}