#include <algorithm>
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef map<int, int> mii;
typedef unordered_map<int, int> umii;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef vector<int> vi;
typedef vector<vector<int>> vc;
typedef vector<long long> vl;
typedef vector<vector<long long>> vll;
typedef __int128_t int128;
#define rep(x, y, z) for(int x = (y); x <= (z); x++)
#define per(x, y ,z) for(int x = (y); x >= (z); x--)
#define yes cout << "Yes\n"
#define no cout << "No\n"

//#define int long long
//const int N = 1e5 + 5;
//const int mod = 1e9 + 7;
//const ll inf = 1e18;


void solve(){
    ll n, k; cin >> n >> k;
    vector<pll> p(n + 1, {0, 0});
    rep(i, 1, n) cin >> p[i].first >> p[i].second;
    sort(p.begin() + 1, p.end());
    ll now = 0;
    rep(i, 1, n){
        now += (p[i].first - p[i-1].first)*k;
        if(now < p[i].second){
            no;
            return;
        }
        else{
            now -= p[i].second;
        }
    }
    yes;
}

signed main(){
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int __ = 1; cin >> __;
    while(__--){
        solve();
    }
    return 0;
}