#include <stdio.h>         
      
#define NMAX 1001000  
#define NN 50050    
#define INFINIT 20000000         
        
long N;         
long long X[NMAX],Y[NMAX],C[NMAX],minim[NN],rez,T,i,j;         
      
int main()         
{         
freopen("gardieni.in","r",stdin);
scanf("%ld %lld\n", &N, &T);
for (i=1;i<=N;++i)
     scanf("%lld %lld %lld\n", &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;         
}