#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;

#define rep(i, a, b) for(int i = (a); i < (b); ++i)
#define all(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define pb push_back

const int maxn = 5e5 + 100;
const int mod = 1e9 + 9;


ll pw(ll a, ll b){
    ll c = 1;
    while(b){
        if(b & 1) c = c * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return c;
}

int n, m;
ull a[maxn];
ull b[maxn];

ull rnd(){
    ull x = 0;
    rep(i, 0, 64){
        x <<= 1;
        if(rand() & 1) x |= 1;
    }
    return x;
}

map<ull, int> cnt;

pii e[maxn];

int p[maxn];

map<ll, bool> vis;

int main(){
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    int t;
    cin >> t;
    while(t--){
        cin >> n >> m;
        vis.clear();
        rep(i, 0, m){
            int v, u;
            cin >> v >> u;
            e[i] = {v, u};
        }
         if(n < 7){
                rep(i, 1, n + 1){
                    p[i] = i;
                }
                do{
                    ll x = 0;
                    rep(i, 0, m){
                        int v = p[e[i].first], u = p[e[i].second];
                        if(v > u) swap(v, u);
                        x |= (1ll << ((v - 1) * 6 + (u - 1)));
                    }
                    vis[x] = 1;
                    if(SZ(vis) > n) break;
                }while(next_permutation(p + 1, p + n + 1));
                if(SZ(vis) > n) cout << "NO\n";
                else cout << "YES\n";
                continue;
            }
        if(m != 1ll * n * (n - 1) / 2 && m != 0) cout << "NO\n";
        else{
            cout << "YES\n";
        }
    }


    return 0;
}