#include <fstream>
#include <algorithm>

using namespace std;

#define inFile "gardieni.in"
#define outFile "gardieni.out"
#define MAX_T 100000

ifstream in(inFile);
ofstream out(outFile);

int minCost[MAX_T + 1];

int main() {
    int N, T, i, j, start, fin, cost;
    
    in >> N >> T;
    for(i = 1; i <= N; i++) {
        in >> start >> fin >> cost;
        for(j = start; j <= fin; j++)
            if(minCost[j] > cost || !minCost[j])
                minCost[j] = cost;
    }
    
    for(i = 1, cost = 0; i <= T; i++)
        cost += minCost[i];
    
    out << cost << '\n';
        
    return 0;
}