#include <bits/stdc++.h>   #define FAST ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);   #define ll long long int   #define pb push_back   #define pob pop_back   #define ub upper_bound   #define lb lower_bound   #define mp make_pair   #define f0(i,n) for(i=0;i<n;i++)   #define rf0(i,n) for(i=n-1;i>=0;i--)   #define f2(i,n) for(i=1;i<n;i++)   #define f1(i,n) for(i=1;i<=n;i++)   #define fab(i,a,b) for(i=a;i<=b;i++)   #define shr  ll t;cin>>t; while(t--)   #define fi first   #define sc second   #define pll pair<ll,ll>   #define vll vector<ll>   #define vpll vector<pll>   #define all(v) v.begin(),v.end()   #define mod 1000000007   #define dev(a) for(auto it:a)cout<<it<<      #define prec(nm,prc) cout<<fixed << setprecision(nm)<<prc   #define print(a) cout<<a<<endl;   #define nl   n    using namespace std;   bool comp(pll &a,pll &b)   {       return (a.sc<b.sc);   }   ll power(ll n,ll p)   {    if(p==0)    return 1;    else    {     ll ans=power(n,p/2)%mod;     ans=(ans*ans)%mod;     if(p%2==0)     return ans;     else     return ans=(ans*n)%mod;    }   }   bool isPrime(ll n)    {        if (n <= 1)            return false;        if (n <= 3)            return true;             if (n % 2 == 0 || n % 3 == 0)            return false;             for (ll i = 5; i * i <= n; i = i + 6)            if (n % i == 0 || n % (i + 2) == 0)                return false;             return true;    }              /********************HAR HAR MAHADEV***********JAI BAJRANG BALI************************/     int main()    {      FAST;      /* ifstream cin;       cin.open( input.txt );       ofstream cout;       cout.open( output.txt );                         */      shr        {           ll i,j,n,a,b,c,c1,d,m,sum=0,temp,k,k2,k1,ans=0,cnt=0,r=0,e=0,f;         string str,stri,om,s;           map<ll,ll>mp,mp1;           set<ll>st; vector<vll> v;           cin>>n>>k; ll x[n][2];           f0(i,n)           {               cin>>x[i][0]>>x[i][1];           }          f0(i,n)          {             vll vk;              f0(j,n)             {                                  if(i!=j)                 {                     vk.pb(abs(x[i][0]-x[j][0])+abs(x[i][1]-x[j][1]));                 }                             }              v.pb(vk);             r++;         }         f0(i,v.size())         {         ll p=*max_element(all(v[i]));         if(p<=k){e=1;break;}         }         if(e==1)cout<<1;         else cout<<-1;         cout<<endl;        }               return 0;     }                         