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#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using pi = pair<int, int>;
using vpi = vector<pi>;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<long long>;
using mpii = map<int, int>;
using mpll = map<ll, ll>;
using db = long double;
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define lb lower_bound
#define ub upper_bound
const int MOD = (int)1e9 + 7;
const db PI = acos((db)-1);
const int dx[4]{1, 0, -1, 0};
const int dy[4]{0, 1, 0, -1};
string solve() {
int n, m;
cin >> n >> m;
vector<vector<bool>> v(n, vector<bool>(n, false));
vpi points;
for (int i = 0; i < m; i++) {
int x, y;
cin >> x >> y;
points.pb(make_pair(x, y));
}
for (auto p : points) {
v[p.first - 1][p.second - 1] = 1;
for (auto pp : points) {
if(pp != p) {
for (int i = 0; i < n; i++) {
v[pp.first - 1][i]=1;
cerr << v[pp.first - 1][i] << endl;
}
for (int i = 0; i < n; i++) {
v[i][pp.second - 1] = 1;
}
}
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (v[i][j] == 0 && (p.first - 1 == i || p.second - 1 == j)) {
return "YES";
}
}
}
}
return "NO";
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int tt;
cin >> tt;
while(tt--) {
cout << solve() << '\n';
}
}
/* stuff you should look for:
---------------------------
* special cases (n=1?)
* int overflow, array bounds
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
* DON'T GET STUCK ON ONE APPROACH
*/
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