#include <bits/stdc++.h>
#include <atcoder/lazysegtree>
using namespace std;

using S = long long;
using F = long long;

const S INF = 8e18;
const F ID = 8e18;

S op(S a, S b){ return std::max(a, b); }
S e(){ return 0; }
S mapping(F f, S x){ return (f == ID ? x : f); }
F composition(F f, F g){ return (f == ID ? g : f); }
F id(){ return ID; }

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N, T; cin >> N >> T;
    vector<array<long long, 3>> PLR(N);
    for (auto& row : PLR) {
        cin >> row[1] >> row[2] >> row[0];
    }
    sort(PLR.begin(), PLR.end());
    const int SIZE = 4 << 17;
    atcoder::lazy_segtree<S, op, e, F, mapping, composition, id> seg(SIZE);
    for (auto [p, l, r] : PLR) {
        seg.apply(l, r + 1, p);
    }
    vector<long long> dp(SIZE + 1, 0);
    for (int i = T; i <= SIZE; i++) {
        dp[i] = max(dp[i - T] + seg.get(i - T), dp[i - 1]);
    }
    cout << dp[SIZE] << endl;
}