#include <bits/stdc++.h>
using namespace std;
#define lli long long int

int x[1005] , y[1005];

int main()
{
    int T; cin>>T;
    while (  T-- )
    {
        int n; lli m;
        cin>>n>>m;
        for ( int i=0 ; i<n ; i++ )
            cin>>y[i]>>x[i];

        int ans = 0;
        {
            lli S = m; //min( 1000 , m );
            vector< pair<int,int> > v;
            for ( int i=0 ; i<n ; i++ ) v.push_back( make_pair( y[i] , x[i] ) );
            sort( v.begin() , v.end() );

            for ( lli h=1 ; h<=S ; h++ )
            {
                lli w = m / h;

                multiset<int> st;
                for ( int i1=0,i2=0 ; i2<n ; i2++ )
                {
                    st.insert( v[i2].second );
                    while ( (v[i2].first - v[i1].first) > h )
                    {
                        st.erase( st.find( v[i1].second ) );
                        i1++;
                    }

                    int cnt = 0;
                    for ( multiset<int>::iterator si=st.begin(),sj=st.begin() ; sj!=st.end() ; sj++ )
                    {
                        cnt++;
                        while ( (*sj - *si) > w ) cnt-- , si++;
                        ans = max( ans , cnt );
                    }
                }
            }
        }

        cout<<ans<<"\n";
    }

    return 0;
}