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

#define int long long

const int mxn = 1e6 + 5;

typedef pair<int, int> pii;

void solve()
{
    int n, k;
    scanf("%lld%lld", &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)
        {
            printf("No\n");
            return;
        }
    }
    printf("Yes\n");
}

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

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

    return 0;
}