// Steins;Gate
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <numeric>
#include <vector>
using namespace std;
#define INF 0x3f3f3f3f
#define ll long long
#define jiasu ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define rep(i, a, b) for (int i = (a); i <= (b); ++i)
#define don(i, a, b) for (int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define endl '\n'
//  Codefores Round #764 Div3  最小或生成树
const int inf = 1e9;
int n, m;
vector<vector<pii>> mp;
int ans;
void dfs(int u, vector<bool>& st) {
    st[u] = 1;
    for (auto e : mp[u]) {
        int v = e.first, w = e.second;
        if (!st[v] && (ans | w) == ans) {
            dfs(v, st);
        }
    }
}
void cnt(int pw) {
    if (pw < 0)
        return;
    int d = 1 << pw;
    ans -= d;  // 尝试删除每一位的1
    vector<bool> st(n, 0);
    dfs(0, st);  // 判断删除后是否连通
    for (auto t : st) {
        if (!t) {
            ans += d;
            break;
        }
    }
    cnt(pw - 1);
}
void solve() {
    cin >> n >> m;
    mp.assign(n, vector<pii>(0));
    rep(i, 1, m) {
        int x, y, w;
        cin >> x >> y >> w;
        x--, y--;
        mp[x].emplace_back(y, w);
        mp[y].emplace_back(x, w);
    }
    ans = 1;
    int bit = 0;
    for (; ans < inf; bit++) {
        ans = ans << 1 | 1;
    }
    // bit:最多左移了多少位
    cnt(bit);
    cout << ans << endl;
}
signed main() {
    jiasu;
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}