#include <iostream>
#include <vector>

using namespace std;

vector<vector<int>> GS;
vector<bool> visited;
int cctvCount = 0;

bool dfs2(int v, int depth)
{
    visited[v] = true;
    const int size = GS[v].size();

    if (depth == 0 && size == 0) { ++cctvCount; return true; }

    bool isOk = false;
    for (int i = 0; i < size; ++i)
    {
        const int go = GS[v][i];
        if (!visited[go]) if (!dfs2(go, depth + 1)) isOk = true;
    }
    if (isOk)
    {
        ++cctvCount;
        return true;
    }
    return false;
}

/*
https://algospot.com/judge/problem/read/GALLERY
*/
int main()
{
    ios::sync_with_stdio(false);
    int T;
    cin >> T;
    while (T-- > 0)
    {
        int G, H;
        cin >> G >> H;
        GS = vector<vector<int>>(G);
        visited = vector<bool>(G, false);
        for (int i = 0; i < H; ++i)
        {
            int u, v;
            cin >> u >> v;
            GS[u].push_back(v);
            GS[v].push_back(u);
        }
        for (int i = 0; i < G; ++i) if (!visited[i]) dfs2(i, 0);
        cout << cctvCount << endl;
        cctvCount = 0;
    }
    return 0;
}

int V;
vector<vector<int>> adj;
vector<bool> visited;
vector<bool> cctv;

int dfs(int v)
{
    visited[v] = true;

    vector<int> child;
    for (int i = 0; i < adj[v].size(); ++i)
    {
        const int go = adj[v][i];
        if (!visited[go])
        {
            const int x = dfs(go);
            child.push_back(go);
        }
    }
    for (auto i : child)
    {
        if (!cctv[i])
        {
            cctv[v] = true;
            break;
        }
    }
    return child.size();
}

int main()
{
    ios::sync_with_stdio(false);
    int T;
    cin >> T;
    while (T--)
    {
        int E;
        cin >> ::V >> E;
        adj = vector<vector<int>>(V);
        visited = cctv = vector<bool>(V, false);
        for (int i = 0; i < E; ++i)
        {
            int u, v;
            cin >> u >> v;
            adj[u].push_back(v);
            adj[v].push_back(u);
        }
        for (int i = 0; i < V; ++i) if (!visited[i]) if(dfs(i) == 0) cctv[i] = true;
        int cctvCount = 0;
        for (int i = 0; i < V; ++i) if (cctv[i]) ++cctvCount;
        cout << cctvCount << endl;
    }
    return 0;
}