#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()
{
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 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 print()
{
freopen("gardieni.out","w",stdout);
printf("%lld\n", rez);
}

int main()
{
read();
solve();
print();
return 0;
}