#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
#define rep(i, n) REP(i, 0, n)
#define REP(i, s, e) for (int i = (s); i < (int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for (int i = (int)(s - 1); i >= (int)(e); i--)
#define all(r) r.begin(), r.end()
#define rall(r) r.rbegin(), r.rend()

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;

template <typename T, typename U>
T chmax(T& a, const U& b) {
    if (a >= b) return false;
    a = b;
    return true;
}
template <typename T, typename U>
T chmin(T& a, const U& b) {
    if (a <= b) return false;
    a = b;
    return true;
}

void yes_no(bool f, string yes = "Yes", string no = "No") { cout << (f ? yes : no) << "\n"; }

void solve() {
    ll n, m;
    cin >> n >> m;
    using P = pair<ll, ll>;
    vector<P> v(m);
    ll sum = 0;
    rep(i, m) {
        ll a, b;
        cin >> a >> b;
        --a;
        v[i] = {a, b};
        sum += b;
    }
    if (sum != n) {
        yes_no(false);
        return;
    }
    P mi = {v[0].first - v[0].second + 1, v[0].first};
    P ma = {v[0].first, v[0].first + v[0].second - 1};
    REP(i, 1, m) {
        auto [a, b] = v[i];
        ll low = a - b + 1;
        ll high = a;
        if (mi.second >= a || ma.second + 1 < low) {
            yes_no(false);
            return;
        }
        chmax(low, mi.second + 1);
        chmin(high, ma.second + 1);
        mi = {low, low + b - 1};
        ma = {high, high + b - 1};
    }
    yes_no(true);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int t = 1;
    cin >> t;
    rep(ti, t) solve();
    return 0;
}