#include <bits/stdc++.h>

using namespace std;

#define rep(i, s, e) for (int i = s; i <= e; ++i)
#define drep(i, s, e) for (int i = s; i >= e; --i)
#define file(a) freopen(#a".in", "r", stdin), freopen(#a".out", "w", stdout)
#define pv(a) cout << #a << " = " << a << endl
#define pa(a, l, r) cout << #a " : "; rep(_, l, r) cout << a[_] << ' '; cout << endl

const int INF = 0x3f3f3f3f;

const int N = 1e6 + 10;

int read() {
  int x = 0, f = 1; char c = getchar();
  for (; c < '0' || c > '9'; c = getchar()) if (c == '-') f = -1;
  for (; c >= '0' && c <= '9'; c = getchar()) x = x * 10 + c - 48;
  return x * f;
}

int n, a[N], b[N], l[N], r[N], o[N];

void solve() {
  n = read();
  rep(i, 1, n) {
    a[i] = read(), b[i] = read();
    l[i] = r[i] = a[i], o[i] = i;
  }
  rep(i, 1, n) {
    int mx = -INF, mn = INF;
    rep(j, 1, n) if (j != i) {
      mx = max(mx, b[j]);
      mn = min(mn, b[j]);
    }
    l[i] += mn, r[i] += mx;
  }
  sort(o + 1, o + n + 1, [](int i, int j) {
    return l[i] == l[j] ? r[i] < r[j] : l[i] < l[j];
  });
  rep(i, 1, n - 1) if (r[o[i]] > l[o[i + 1]]) {
    printf("No\n");
    return;
  }
  printf("Yes\n");
}

int main() {
  for (int tc = read(); tc; -- tc) solve();
  return 0;
}