#include <stdio.h>      
     
#define NMAX 50005      
#define NN 1000000      
#define INFINIT 10000010      
     
long N;      
long long X[NMAX],Y[NMAX],C[NMAX],minim[NN],rez,T;      
     
void read_data()      
{      
long long i;      
     
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]);      
}      
     
void solve()      
{      
long long i,j;      
     
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];      
}      
     
void write_data()      
{      
freopen("gardieni.out","w",stdout);      
printf("%lld\n", rez);      
}      
     
int main()      
{      
read_data();      
solve();      
write_data();      
return 0;      
}