#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<vvvl> vvvvl;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<vvvb> vvvvb;
typedef pair<ll,ll> pl;
typedef pair<ll,pl> ppl;
typedef pair<ll,ppl> pppl;
typedef pair<ll,pppl> pppppl;
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(a) begin(a),end(a)
#define F first
#define S second
const ll mod=998244353;
const string als="abcdefghijklmnopqrstuvwxyz";
const string ALS="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const ll alb=1000000000;

void ans(int n,int m){
	vector<pair<int,int>> v(m);
	rep(i,0,m){
		cin>>v[i].F>>v[i].S;
	}
	sort(v.begin(),v.end());
	int y=v[0].F;
	rep(i,0,m){
		v[i].F=v[i].F-y;
	}
	
	int z=v[m-1].F;
	z=n-z;
	int s=0;
	rep(i,0,m){
		s=s+v[i].S;
	}
	if(s!=n){
		cout<<"No"<<endl;
		return;
	}
	s=0;
	rep(i,0,m-1){
		s=s+v[i].S;
		if(z+v[i+1].F-1<s){
			cout<<"No"<<endl;
			return;
		}
		if(v[i].F+1>s){
			cout<<"No"<<endl;
			return;
		}
	}
	cout<<"Yes"<<endl;
	return;
}

int main(){
	int t;
	cin>>t;
	rep(ujbaf,0,t){
		int n,m;
		cin>>n>>m;
		ans(n,m);
	}
}