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

using ll = int64_t;

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

	int N, K;
	cin >> N >> K;
	vector<tuple<int, int, ll>> stuff(N);
	ll total = 0;
	vector<int> vals;
	for (auto& [r, l, w] : stuff) {
		cin >> l >> r >> w;
		vals.push_back(l);
		vals.push_back(r);
		total += w;
	}
	vals.push_back(0);
	sort(vals.begin(), vals.end());
	vals.erase(unique(vals.begin(), vals.end()), vals.end());
	auto lookup = [&](int x) -> int {
		return int(lower_bound(vals.begin(), vals.end(), x) - vals.begin());
	};
	for (auto& [r, l, w] : stuff) {
		r = lookup(r);
		l = lookup(l);
	}
	sort(stuff.begin(), stuff.end());

	int X = int(vals.size());
	vector<ll> dp(X);
	for (int x = 0; x < X; x++) {
		priority_queue<ll, vector<ll>, greater<ll>> pq;
		ll s = 0;
		for (auto [r, l, w] : stuff) {
			if (l > x) {
				pq.push(w);
				s += w;
				while (int(pq.size()) > K) {
					s -= pq.top();
					pq.pop();
				}
				dp[r] = max(dp[r], s + dp[x]);
			}
		}
	}
	ll max_left = *max_element(dp.begin(), dp.end());
	ll ans = total - max_left;
	cout << ans << '\n';

	return 0;
}