#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <iomanip>
using namespace std;

const int N = 2e5 + 5, inf = 1e9;
#define pb push_back
#define mp make_pair
#define ll long long
#define ff first
#define ss second
#define all(a) a.begin(),a.end()
#define sz(x) (int)x.size()
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;

void solve(){
    int n, m;
    cin >> n >> m;

    int mx = 0, mn = 1e9;
    int a[n + 5];
    for(int i = 0; i <= n + 2; i++) a[i] = 0;
    for(int i = 0; i < m; i++){
        int p, q;
        cin >> p >> q;
        a[p]++; a[q]++;
    }

    for(int i = 1; i <= n; i++){
        if(a[i] > mx) mx = a[i];
        if(a[i] < mn) mn = a[i];
    }
    
    if(m == 0){
        cout << "YES\n";
        return;
    }
    
    if(1LL * m == 1LL * n * (n - 1) / 2){
        cout << "YES\n";
        return;
    }

    if(mx == m && n == m + 1){
        cout << "YES\n";
        return;
    }
    if(mn == 0 && 1LL * m == 1LL * (n - 1) * (n - 2) / 2){
        cout << "YES\n";
        return;
    }   

    if(n == 1){
        cout << "YES\n";
        return;
    }
    if(n == 2){
        cout << "YES\n";
        return;
    }
    if(n == 3){
        cout << "YES\n";
        return;
    }
    if(n == 4){
        for(int i = 1; i <= 4; i++){
            if(a[i] != 1){
                cout << "NO\n";
                return;
            }
        }
        cout << "YES\n";
        return;
    }
    cout << "NO\n";
    return;
}

int main(){
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int t = 1;
    cin >> t;
    while(t--){
        solve();
    }
    return 0;
}