#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
using namespace std;

const int mxn = 1e6 + 5;

typedef pair<int, int> pii;

void solve()
{
	int n, k;
	cin >> n >> k;
	vector<pii> v(n + 1);
	v[0] = { 0,0 };
	for (int i = 1; i <= n; i++)
	{
		cin >> v[i].first >> v[i].second;
	}
	sort(v.begin(), v.end());
	int sum = 0;
	for (int i = 1; i <= n; i++)
	{
		sum += k * (v[i].first - v[i - 1].first);
		sum -= v[i].second;
		if (sum < 0)
		{
			cout << "No\n";
			return;
		}
	}
	cout << "Yes\n";
}

signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);

	int T = 1;
	scanf("%d", &T);
	while (T--)
	{
		solve();
	}

	return 0;
}