#include<bits/stdc++.h>   using namespace std;   #define inf 1999999999999999999   #define mod 1000000007   #define lb lower_bound   #define ub upper_bound   #define pb push_back   #define pf push_front   #define bn binary_search   #define pq priority_queue   #define int long long   #define pii pair<int,int>   #define mii map<int,int>   #define umii unordered_map<int,int>   #define um unordered_map   #define vi vector<int>   #define mii map<int,int>   #define si set<int>   #define ft first   #define sc second   #define gcd(a,b) __gcd(a,b)   #define lcm(a,b) a*(b/gcd(a,b))   #define bp(a) __builtin_popcountll(a)   #define mmst(a,b) memset(a,b,sizeof(a))   #define ld long double   void lc(){cout<<endl;}   int md(int n){return n%mod;}   void solve()   {    int n;    ld k;    cin>>n>>k;    //k=k*((ld)(sqrt(2)));    pii p[n];    for(int i=0;i<n;i++)    cin>>p[i].ft>>p[i].sc;    for(int i=0;i<n;i++)    {     int mind=0;     for(int j=0;j<n;j++)     {      if(i==j)continue;      int dis=abs(p[i].ft-p[j].ft)+abs(p[i].sc-p[j].sc);      mind=max(mind,dis);     }     if(mind<=k)      {       cout<< 1 ;       return;      }    }       cout<< -1 ;       }   signed main()   {     ios::sync_with_stdio(0);    cin.tie(0);    int t=1;    cin>>t;    while(t--)    {      solve();      lc();    }   }