#include <stdio.h>   
  
#define NMAX 1<<16   
#define NN 1<<20   
#define INFINIT 100000010   
  
long N;
long long X[NMAX],Y[NMAX],C[NMAX],minim[NN],T; 
long long rez;  
  
int main()   
{   
long i,j;
freopen("gardieni.in","r",stdin);
scanf("%ld %lld",&N,&T);

for (i=1;i<=N;++i)
     scanf("%lld %lld %lld",&X[i],&Y[i],&C[i]);
for (i=1;i<=T;++i)
     minim[i]=INFINIT;
for (i=1;i<=N;++i)
     {
     for (j=X[i];j<=Y[i];++j)
      if (minim[j]>C[i])
          minim[j]=C[i];
      }

rez=0;
for (i=1;i<=T;++i)
    rez+=minim[i];  
freopen("gardieni.out","w",stdout);
printf("%lld\n", rez);   
return 0;   
}