#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 1LL << 60;
#define all(a) begin(a), end(a)
#define sz(a) ssize(a)
template<class T, class U> bool chmin(T& a, U b) { return a > b ? a = b, 1 : 0; }
template<class T, class U> bool chmax(T& a, U b) { return a < b ? a = b, 1 : 0; }
using pll = pair<ll, ll>;
using vpll = vector<pll>;
using vll = vector<ll>;
using vvll = vector<vll>;
#define _O(_1, _2, _3, n, ...) n
#define _r1(i, n) for(ll i = 0; i < (ll)(n); i++)
#define _r2(i, l, r) for(ll i = (ll)(l); i < (ll)(r); i++)
#define rep(...) _O(__VA_ARGS__, _r2, _r1)(__VA_ARGS__)
#define _rr1(i, n) for(ll i = (ll)(n) - 1; i >= 0; i--)
#define _rr2(i, l, r) for(ll i = (ll)(r) - 1; i >= (ll)(l); i--)
#define rrep(...) _O(__VA_ARGS__, _rr2, _rr1)(__VA_ARGS__)
template<class T> ostream& operator<<(ostream& o, const vector<T>& v) {
   ll i = 0;
   for(auto& x : v) o << (i++ ? " " : "") << x;
   return o;
}
template<class H, class... T> void out(const H& h, const T&... t) {
   cout << h;
   ((cout << " " << t), ...);
   cout << endl;
}

int main(){
  ll t; cin >> t;
  while(t--){
    ll n, m; cin >> n >> m;
    vll a(m), b(m); rep(i,m) cin >> a[i] >> b[i];
    ll l = -INF, r = INF;
    ll pre = 0;
    rep(i,m){
      ll nxt = pre + b[i];
      chmax(l,a[i]-nxt);
      chmin(r,a[i]-pre);
      pre = nxt;
    }
    out(l < r ? "Yes" : "No");
  }
}