#include <cstdio>
#include <algorithm>

using namespace std;

#define maxn 1000010

int n, i, j, k, t;
int v[maxn];
long long sol;

int main()
{
    freopen("gardieni.in", "r", stdin);
    freopen("gardieni.out", "w", stdout);

    scanf("%d%d", &n, &t);
    for(int i=1; i<=t; ++i)
        v[i]=1000000000;

    for(int i=1; i<=n; ++i)
    {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        for(int j=a; j<=b; ++j)
            v[j]=min(v[j], c);
    }

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

    printf("%lld\n", sol);

    return 0;
}