//gardieni
#include<stdio.h>
FILE*fin=fopen("gardieni.in","r");
FILE*fout=fopen("gardieni.out","w");
int main()
{
long long sum=0;
long t,n,v[1000001],i,j,a,b,c;
fscanf(fin,"%ld%ld",&n,&t);
for(i=1;i<=t;i++)
  v[i]=200000000;
for(i=1;i<=n;i++)
{
  fscanf(fin,"%ld%ld%ld",&a,&b,&c);
  for(j=a;j<=b;j++)
    if(c<v[j]) v[j]=c;
}
for(i=1;i<=t;i++)
  sum+=v[i];
fprintf(fout,"%lld",sum);
fclose(fin);
fclose(fout);
return 0;
}