#include <cstdio>
#include <climits>

long v[100000010], a, b, c, t, n;
int main ()
{
	int i;


	FILE *f = fopen("gardieni.in", "r");
	fscanf(f, "%ld%ld", &n, &t);

	for (i = 1; i <= t; i++)
		v[i] = LONG_MAX;

	for (int s = 1; s <= n; s++)
	{
		fscanf(f, "%ld%ld%ld", &a, &b, &c);
		for (i = a; i <= b; i++)
			if (c < v[i])
				v[i] = c;
	}
	fclose(f);
	int sum = 0;
	for (i = 1; i <= t; i++)
		sum += v[i];

	f = fopen("gardieni.out", "w");
	fprintf(f, "%d", sum);
	fclose(f);
	return 0;
}