// Hallelujah, praise the one who set me free
// Hallelujah, death has lost its grip on me
// You have broken every chain, There's salvation in your name
// Jesus Christ, my living hope
#include <bits/stdc++.h> 
using namespace std;

#define REP(i, s, e) for (int i = (s); i < (e); i++)
#define RREP(i, s, e) for (int i = (s); i >= (e); i--)
template <class T>
inline bool mnto(T& a, T b) {return a > b ? a = b, 1 : 0;}
template <class T>
inline bool mxto(T& a, T b) {return a < b ? a = b, 1: 0;}
typedef long long ll;
typedef long double ld;
#define FI first
#define SE second
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
#define ALL(_a) _a.begin(), _a.end()
#define SZ(_a) (int) _a.size()
#define pb push_back
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ii> vii;
typedef vector<iii> viii;

#ifndef DEBUG
#define cerr if (0) cerr
#endif

const int INF = 1000000005;
const ll LINF = 1000000000000000005ll;
const int MAXN = 200005;

int t;
int n, m;
vii eg;

int main() {
#ifndef DEBUG
    ios::sync_with_stdio(0), cin.tie(0);
#endif
    cin >> t;
    while (t--) {
        cin >> n >> m;
        eg = vii(m);
        REP (i, 0, m) {
            cin >> eg[i].FI >> eg[i].SE;
            if (eg[i].FI > eg[i].SE) {
                swap(eg[i].FI, eg[i].SE);
            }
        }
        sort(ALL(eg));
        if (m == 0 || m == (ll) n * (n - 1) / 2) {
            cout << "YES\n";
            continue;
        }
        if (n > 5) {
            cout << "NO\n";
            continue;
        }
        vi p(n, 0);
        iota(ALL(p), 1);
        set<vii> st;
        do {
            vii teg;
            for (auto [u, v] : eg) {
                int nu = p[u - 1], nv = p[v - 1];
                if (nu > nv) {
                    swap(nu, nv);
                }
                teg.pb({nu, nv});
            }
            sort(ALL(teg));
            st.insert(teg);
            if (SZ(st) > n) {
                break;
            }
        } while (next_permutation(ALL(p)));
        if (SZ(st) > n) {
            cout << "NO\n";
        } else {
            cout << "YES\n";
        }
        /*
        int ans = 0;
        REP (i, 0, 1 << (n * (n - 1) / 2)) {
            if (__builtin_popcount(i) != m) {
                continue;
            }
            int ptr = 0;
            vii neg;
            REP (j, 0, n) {
                REP (k, j + 1, n) {
                    if (i >> ptr & 1) {
                        neg.pb({j, k});
                    }
                    ptr++;
                }
            }
            assert(SZ(neg) == m);
            vi p(n, 0);
            iota(ALL(p), 1);
            bool fnd = 0;
            do {
                vii teg;
                for (auto [u, v] : neg) {
                    int nu = p[u], nv = p[v];
                    if (nu > nv) {
                        swap(nu, nv);
                    }
                    teg.pb({nu, nv});
                }
                sort(ALL(teg));
                if (teg == eg) {
                    fnd = 1;
                    break;
                }
            } while (next_permutation(ALL(p)));
            ans += fnd;
            if (ans > n) {
                break;
            }
        }
        cerr << ans << '\n';
        if (ans > n) {
            cout << "NO\n";
        } else {
            cout << "YES\n";
        }
        */
    }
    return 0;
}