#include <bits/stdc++.h>
#include <atcoder/modint.hpp>
using namespace std;

using i32 = int;
using i64 = long long;
using i128 = __int128_t;
using f64 = double;
using p2 = pair<i64, i64>;
using p3 = tuple<i64, i64, i64>;
using mint = atcoder::modint998244353;
constexpr i64 inf = 1e18;

void _main();
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(18);
  _main();
}

void _main() {
  i64 tt;
  cin >> tt;
  for (;tt--;) {
    i64 n, m;
    cin >> n >> m;
    vector<p2> ab(m);
    for (i64 i = 0; i < m; i++) {
      i64 a, b;
      cin >> a >> b;
      a--;
      ab[i] = {a, b};
    }
    ab.push_back(ab[0]);
    ab.back().first += n;
    i64 l = 0, r = inf;
    for (i64 i = m; i >= 0; i--) {
      auto [a, b] = ab[i];
      auto [c, d] = ab[i + 1];
      l = max(l, a + 1);
      i64 nl = l - b, nr = r - b;
      nr = min(nr, a);
      nl = max(nl, a - b + 1);
      l = nl, r = nr;
    }
    if (l > r) {
      cout << "No\n";
      continue;
    }
    cout << "Yes\n";
  }
}