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

struct iofast_t {
    iofast_t() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} iofast;

struct uns_t {} uns;
template <typename Element, typename Head, typename ...Args>
auto vec(Element init, Head arg, Args ...args) {
    if constexpr (sizeof...(Args) == 0) return std::vector(arg, init);
    else return std::vector(arg, vec(init, args...));
}
template <typename Element, typename Head, typename ...Args>
auto vec(uns_t, Head arg, Args ...args) {
    return vec(Element(), arg, args...);
}

template <typename T, typename Compare = less<T>>
T &chmin(T &l, T r, Compare &&f = less<T>()) { return l = min(l, r, f); }
template <typename T, typename Compare = less<T>>
T &chmax(T &l, T r, Compare &&f = less<T>()) { return l = max(l, r, f); }

int main() {
    int t; cin >> t;

    while (t--) {
        int n, m; cin >> n >> m;

        auto deg = vec<int>(0, n);
        for (int i = 0; i < m; ++i) {
            int u, v; cin >> u >> v; --u; --v;
            ++deg[u];
            ++deg[v];
        }

        bool ans = false;

        map<int, bool> found;
        for (auto v : deg) {
            ans |= found[v];
            found[v] = true;
        }

        cout << (ans ? "Yes" : "No") << endl;
    }
}