#include<stdio.h>
FILE*f=fopen("gardieni.in","r");
FILE*g=fopen("gardieni.out","w");
int n,t,a,b,c,v[1000002];
long long s;
int main()
{
	fscanf(f,"%d%d",&n,&t);
	for(int i=1;i<=t;++i)
		v[i]=10000000;
	for(int i=1;i<=n;++i)
	{
		fscanf(f,"%d%d%d",&a,&b,&c);
		for(int j=a;j<=b;++j)
			if(c<v[j])
				v[j]=c;
	}
	
	for(int i=1;i<=t;++i)
		s+=v[i];
	
	fprintf(g,"%lld",s);
	
	
	
	fclose(f);
	fclose(g);
	return 0;
}