#include <stdio.h>      
     
#define INFINIT 0x3f3f3f3f       
     
int N;   
long long rez=0;   
int X[51000],Y[51000],C[51000],minim[1000100],T;    
     
int main()      
{      
int i,j;       
freopen("gardieni.in","r",stdin);   
scanf("%d %d",&N,&T);   
for (i=1;i<=N;++i)   
     scanf("%d %d %d",&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];   
      }   
for (i=1;i<=T;++i)   
    rez+=minim[i];     
freopen("gardieni.out","w",stdout);   
printf("%lld\n", rez);      
return 0;      
}