import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class Main {

    public static List<ArrayList<Integer>> junctions = new ArrayList<ArrayList<Integer>>();
    public static boolean[] installs; 
    public static int cameraCount;

    public static void main(String[] args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int cases = Integer.parseInt(br.readLine());

        for(int i=0; i<cases; i++){

            String[] inputs = br.readLine().split(" ");
            int galleryCount = Integer.parseInt(inputs[0]);
            int passageCount = Integer.parseInt(inputs[1]);
            installs = new boolean[galleryCount];

            for(int j=0; j<galleryCount; j++){
                ArrayList<Integer> list = new ArrayList<Integer>();
                list.add(j);
                junctions.add(list);
            }

            for(int j=0; j<passageCount; j++){

                String[] galleries = br.readLine().split(" ");
                int parent, child; 
                int gallery1 = Integer.parseInt(galleries[0]);
                int gallery2 = Integer.parseInt(galleries[1]);

                if(gallery1 < gallery2){
                    parent = gallery1;
                    child = gallery2;
                }else{
                    parent = gallery2;
                    child = gallery1;
                }

                junctions.get(parent).add(child);
            }

            int junctionsSize = junctions.size();
            for(int j=0; j<junctionsSize; j++){
                setCamera(junctions.get(j));
            }

            System.out.println(cameraCount);
        }
    }

    public static void setCamera(List<Integer> list){
        int size = list.size();
        int value;
        boolean isChecked = false;

        for(int i=0; i<size; i++){
            value = list.get(i);
            for(int j=0; j<installs.length; j++){
                if(installs[value] == false){
                    isChecked = true;
                    installs[value] = true;
                }
            }
        }
        if(isChecked){
            cameraCount++;
        }
    }
}