import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;

public class mrpresident {
	static int[] arrow;

	static int find(int person) {
		if (arrow[person] == -1) {
			return person;
		}
		arrow[person] = find(arrow[person]);
		return arrow[person];
	}

	static void combineGroup(int person1, int person2) {
		person1 = find(person1);
		person2 = find(person2);
		arrow[person1] = person2;
	}

	static class Edge implements Comparable<Edge> {
		int cityA, cityB;// cities it connects
		long cost;// cost

		@Override
		public int compareTo(Edge other) {
			return Long.compare(cost, other.cost);
		}
	}

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] line = br.readLine().split(" ");
		int n = Integer.parseInt(line[0]);
		int m = Integer.parseInt(line[1]);
		long k = Long.parseLong(line[2]);

		// initialize disjoint set
		arrow = new int[n + 6];
		Arrays.fill(arrow, -1);

		ArrayList<Edge> roads = new ArrayList<Edge>();

		// read in roads
		for (int i = 0; i < m; i++) {
			// read in line
			line = br.readLine().split(" ");
			Edge road = new Edge();
			road.cityA = Integer.parseInt(line[0]) - 1;
			road.cityB = Integer.parseInt(line[1]) - 1;
			road.cost = Long.parseLong(line[2]);
			roads.add(road);
		}

		// sort from least to most expensive
		Collections.sort(roads);

		// kruskals algorithm
		ArrayList<Edge> keptRoads = new ArrayList<Edge>();
		long totalCost = 0;
		for (Edge road : roads) {
			if (find(road.cityA) != find(road.cityB)) {
				keptRoads.add(road);
				totalCost += road.cost;
				combineGroup(road.cityA, road.cityB);
			}
		}

		// check if possible
		if (keptRoads.size() != n - 1) {
			System.out.println(-1);
			return;
		}

		Collections.sort(keptRoads);
		Collections.reverse(keptRoads);

		// start from most expensive road, and see if we need to transform it to a super
		// road
		int superRoadsUsed = 0;
		for (Edge road : keptRoads) {
			if (totalCost <= k) {
				break;
			}
			totalCost -= road.cost;
			totalCost += 1;
			superRoadsUsed++;
		}

		// not enough money
		if (totalCost > k) {
			System.out.println(-1);
			return;
		}

		System.out.println(superRoadsUsed);
	}

}