#include
     
      #include
      
       #include
       
        using namespace std;int map[21][21];int a[21][21];bool used[21][21];int n,m;bool dfs(){    int i,j;    int x,y,r;    int flag=0;    for(i=1;i<=n;i++)    {        if(flag) break;        for(j=1;j<=n;j++)            if(!used[i][j])            {                x=i;y=j;                flag=1;                break;            }    }    int x1,y1;    for(r=0;;r++)    {        x1=x+r;y1=y+r;        if(x1>n||y1>n) break;        if(a[x1][y1]-a[x1][y-1]-a[x-1][y1]+a[x-1][y-1]>1) break;        if(a[x1][y1]-a[x1][y-1]-a[x-1][y1]+a[x-1][y-1]==1)        {            for(i=x;i<=x1;i++)                for(j=y;j<=y1;j++)                    used[i][j]=1;            if(dfs()) return 1;            for(i=x;i<=x1;i++)                for(j=y;j<=y1;j++)                    used[i][j]=0;        }    }    for(i=1;i<=n;i++)        for(j=1;j<=n;j++)            if(!used[i][j])                return 0;    return 1;}int main(){    int cas,x,y;    scanf("%d",&cas);    while(cas--)    {        memset(map,0,sizeof(map));        scanf("%d%d",&n,&m);        while(m--)        {            scanf("%d%d",&x,&y);            map[x][y]=1;        }        memset(a,0,sizeof(a));        for(int i=1;i<=n;i++)            for(int j=1;j<=n;j++)                a[i][j]=a[i-1][j]+a[i][j-1]-a[i-1][j-1]+map[i][j];        memset(used,0,sizeof(used));        int c=dfs();        if(c==1) printf("YES\n");        if(c==0) printf("NO\n");    }    return 0;}