#include <fstream>

#define lint long long int
using namespace std;

class InputReader {
    public:
        InputReader() {}
        InputReader(const char *file_name) {
            input_file = fopen(file_name, "r");
            cursor = 0;
            fread(buffer, SIZE, 1, input_file);
        }
        inline InputReader &operator >>(int &n) {
            while(buffer[cursor] < '0' || buffer[cursor] > '9') {
                advance();
            }
            n = 0;
            while('0' <= buffer[cursor] && buffer[cursor] <= '9') {
                n = n * 10 + buffer[cursor] - '0';
                advance();
            }
            return *this;
        }
    private:
        FILE *input_file;
        static const int SIZE = 1 << 17;
        int cursor;
        char buffer[SIZE];
        inline void advance() {
            ++ cursor;
            if(cursor == SIZE) {
                cursor = 0;
                fread(buffer, SIZE, 1, input_file);
            }
        }
};

const int NMAX = 50005;
const int TMAX = 1000005;

int best[TMAX];

int main()
{
    InputReader cin("gardieni.in");
    ofstream cout("gardieni.out");

    int n = 0, t = 0;
    cin >> n >> t;

    int a, b, c;
    while (n --) {
        cin >> a >> b >> c;

        while (a <= b) {
            if (!best[a] || c < best[a])
                best[a] = c;
            ++ a;
        }
    }

    lint ans = 0;
    for (int i = 1; i <= t; ++ i)
        ans += best[i];

    cout << ans << '\n';

    //cin.close();
    cout.close();
    return 0;
}