1 #include<bits/stdc++.h>
2 #define rg register
3 using namespace std;
4 const int N = 2e5 + 10;
5 map<int, int> mp;
6 int n, m;
7 void solve()
8 {
9 for(rg int i = 1 ; i <= m ; i++){
10 int x, y; cin >> x >> y;
11 mp[y] += x;
12 }
13 int last = 0, tag = 0;//tag表示前一格对当前格子的影响
14 for(auto x : mp){
15 if(x.second == 3){//当前满的
16 if(tag != 0){//前面一格戳出来，无解
17 cout << "NO" << endl;
18 return ;
19 }
20 }else if(tag > 0){//当前不满，前一格戳出来
21 // 1010 1000
22 // 0000 0001 这两种不成立
23 if((x.second + tag == 3 && (x.first - last) % 2 > 0) || (x.second == tag && (x.first - last) % 2 == 0)){
24 cout << "NO" << endl;
25 return ;
26 }
27 tag = 0;
28 last = x.first;
29 }else{//当前不满，前一格对当前无影响，全空
30 tag = x.second;
31 last = x.first;
32 }
33 }
34 if(tag == 0){//空的
35 cout << "YES" << endl;
36 }else{
37 cout << "NO" << endl;
38 }
39 }
40
41 int main(){
42 cin.tie(0);
43 ios_base::sync_with_stdio(0);
44 int T; cin >> T;
45 while(T--)
46 {
47 cin >> n >> m;
48 solve();
49 mp.clear();
50 }
51 return 0;
52 }