#include <iostream>

 #include <cstdio>

 #include <climits>

 #include <cstring>

 #include <cstdlib>

 #include <cmath>

 #include <vector>

 #include <queue>

 #include <algorithm>

 #define esp 1e-6

 #define pb push_back

 #define in  freopen("in.txt", "r", stdin);

 #define out freopen("out.txt", "w", stdout);

 #define print(a) printf("%d\n",(a));

 #define bug puts("********))))))");

 #define Rep(i, c) for(__typeof(c.end()) i = c.begin(); i != c.end(); i++)

 #define inf LLONG_MAX

 #define INF 0x0f0f0f0f0f0f

 using namespace std;

 typedef long long  LL;

 typedef vector<int> VI;

 typedef vector<int>:: iterator IT;

 #define N 30010

 #define M 501000

 VI g[N], ss;

 int vis[N], ans, temp;

 void init(void)

 {

     ans = ;

     memset(vis, , sizeof(vis));

 }

 void bfs(int u)

 {

     temp = ;

     vis[u] = ;

     queue<int> q;

     q.push(u);

     while(!q.empty())

     {

         int i;

         i = q.front();

         q.pop();

         Rep(k, g[i])

         {

             if(!vis[*k])

                 vis[*k] = ,temp++, q.push(*k);

         }

     }

 }

 int main(void)

 {

     int T;

     for(int t = scanf("%d", &T); t <= T ; t++)

     {

         for(int i = ; i < N; i++)

             g[i].clear();

         ss.clear();

         init();

         int n, m;

         scanf("%d%d", &n, &m);

         while(m--)

         {

             int u, v;

             scanf("%d%d", &u, &v);

             g[u].pb(v);

             g[v].pb(u);

             ss.pb(u),ss.pb(v);

         }

         Rep(i, ss)

         {

             temp = ;

             if(!vis[*i])

                 bfs(*i);

             ans = max(temp, ans);

         }

         printf("%d\n", ans);

     }

     return ;

 }