#include <fstream>
#include <algorithm>

using namespace std;

#define inFile "gardieni.in"
#define outFile "gardieni.out"
#define MAX_T 1000000
#define INF 0x7fffffff

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

int minCost[MAX_T + 1];

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