#include<cstdio>
#include<algorithm>
#include<cstring>
#include<vector>
using namespace std;

int sol[40],n,i,j,k,x,y,t,m,rez;
vector<int>v[40];
bool viz[40][40];

bool ok(int x,int y)
{
    for (int i=1;i<=y;i++) if (viz[sol[i]][x] || viz[x][sol[i]]) return false;
    return true;
}

void back(int lungime)
{
    rez=max(rez,lungime);
    if (lungime==1)
      {
          for (int i=1;i<=n;i++)
           if (ok(i,lungime))
            {
                sol[lungime]=i;
                back(lungime+1);
                sol[lungime]=0;
            }
   } else
    for (int i=0;i<v[sol[lungime-1]].size();i++)
        if (ok(v[sol[lungime-1]][i],lungime))
            {
                sol[lungime]=v[sol[lungime-1]][i];
                back(lungime+1);
                sol[lungime]=0;
            }
}

int main()
{
    freopen("alianta.in","r",stdin);
    freopen("alianta.out","w",stdout);
    scanf("%d",&t);
    for (t;t>=1;t--)
    {
        scanf("%d %d",&n,&m);
        for (i=1;i<=n;i++) v[i].clear();
        memset(viz,false,sizeof(viz));
        for (i=1;i<=m;i++)
            scanf("%d %d",&x,&y),viz[x][y]=viz[y][x]=true;
        k=0;rez=0;
        for (i=1;i<=n-1;i++)
            for (j=i+1;j<=n;j++)
                if (!viz[i][j])
                    v[i].push_back(j);
        back(1);
        printf("%d\n",rez-1);
    }
    return 0;
}