import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Map;
import java.util.TreeMap;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
		int n = Integer.parseInt(sa[0]);
		int m = Integer.parseInt(sa[1]);
		int l = Integer.parseInt(sa[2]);
		int[] x = new int[n];
		int[] v = new int[n];
		int[] w = new int[n];
		for (int i = 0; i < n; i++) {
			sa = br.readLine().split(" ");
			x[i] = Integer.parseInt(sa[0]);
			v[i] = Integer.parseInt(sa[1]);
			w[i] = Integer.parseInt(sa[2]);
		}
		br.close();

		if ((n + 1) * m < l) {
			System.out.println(-1);
			return;
		}

		TreeMap<Integer, Long> map = new TreeMap<>();
		map.put(m, 0L);
		for (int i = 0; i < n; i++) {
			Map<Integer, Long> tm = map.tailMap(x[i]);
			if (tm.isEmpty()) {
				System.out.println(-1);
				return;
			}
			for (Integer o : tm.keySet().toArray(new Integer[0])) {
				int k = Math.min(x[i] + m, o + v[i]);
				if (map.containsKey(k)) {
					map.put(k, Math.min(map.get(k), tm.get(o) + w[i]));
				} else {
					map.put(k, tm.get(o) + w[i]);
				}
			}
		}

		long ans = Long.MAX_VALUE;
		Map<Integer, Long> tm = map.tailMap(l);
		if (tm.isEmpty()) {
			System.out.println(-1);
			return;
		}
		for (long val : tm.values()) {
			ans = Math.min(ans, val);
		}
		System.out.println(ans);
	}
}