#include<bits/stdc++.h>
#define LL long long
#define ULL unsigned long long#define scl(i) scanf("%lld", &i)
#define scll(i, j) scanf("%lld %lld", &i, &j)
#define sclll(i, j, k) scanf("%lld %lld %lld", &i, &j, &k)
#define scllll(i, j, k, l) scanf("%lld %lld %lld %lld", &i, &j, &k, &l)#define scs(i) scanf("%s", i)
#define sci(i) scanf("%d", &i)
#define scd(i) scanf("%lf", &i)
#define scIl(i) scanf("%I64d", &i)
#define scii(i, j) scanf("%d %d", &i, &j)
#define scdd(i, j) scanf("%lf %lf", &i, &j)
#define scIll(i, j) scanf("%I64d %I64d", &i, &j)
#define sciii(i, j, k) scanf("%d %d %d", &i, &j, &k)
#define scddd(i, j, k) scanf("%lf %lf %lf", &i, &j, &k)
#define scIlll(i, j, k) scanf("%I64d %I64d %I64d", &i, &j, &k)
#define sciiii(i, j, k, l) scanf("%d %d %d %d", &i, &j, &k, &l)
#define scdddd(i, j, k, l) scanf("%lf %lf %lf %lf", &i, &j, &k, &l)
#define scIllll(i, j, k, l) scanf("%I64d %I64d %I64d %I64d", &i, &j, &k, &l)#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1
#define lowbit(i) (i & (-i))
#define mem(i, j) memset(i, j, sizeof(i))#define fir first
#define sec second
#define VI vector<int>
#define ins(i) insert(i)
#define pb(i) push_back(i)
#define pii pair<int, int>
#define VL vector<long long>
#define mk(i, j) make_pair(i, j)
#define all(i) i.begin(), i.end()
#define pll pair<long long, long long>#define _TIME 0
#define _INPUT 0
#define _OUTPUT 0
clock_t START, END;
void __stTIME();
void __enTIME();
void __IOPUT();
using namespace std;const int maxn = 5e4 + 10;struct EDGE{ int v, nxt; LL w; }Edge[maxn<<2];int Head[maxn], EdgeCnt = 0;int n, m;inline void EdgeInit()
{mem(Head, -1);EdgeCnt = 0;
}inline void AddEdge(int from, int to, LL weight)
{int & cnt = EdgeCnt;Edge[cnt].v = to;Edge[cnt].w = weight;Edge[cnt].nxt = Head[from];Head[from] = cnt++;
}struct L_B {LL d[65], p[65];int cnt;void init() {memset(d, 0, sizeof(d));memset(p, 0, sizeof(p));cnt = 0;}  // 1e18以内的数都适用.bool Insert(LL val) {for (int i = 63 ; i >= 0 ; i --) {if (val & (1ll << i)) {if (!d[i]) {d[i]=val;break;}val^=d[i];}}return val > 0;// 可判断val是否存在于线性基当中.
    }LL query_max() {LL res = 0;for (int i = 63 ; i >= 0 ; i --) {if ((res^d[i]) > res) res ^= d[i];}return res;}LL query_min() {  // 应该预先判断能否是0的情况..QAQfor (int i = 0 ; i <= 60 ; i ++) {if (d[i]) return d[i];}return 0;}void rebuild() { // 用于求第k小值.需要先进行独立预处理for (int i = 60 ; i >= 0 ; i --) {for (int j = i-1 ; j >= 0 ; j --) {if (d[i] & (1ll<<j)) d[i] ^= d[j];}}for (int i = 0 ; i <= 60 ; i ++) {if (d[i]) p[cnt++]=d[i];}}LL kthquery(LL k) { // 注意判断原序列异或出0的情况, 此时应该将k -- 在进行后面的操作.LL res = 0;if (k >= (1ll << cnt)) return -1;for (int i = 60 ; i >= 0 ; i --) {if (k & (1LL<<i)) res ^= p[i];}return res;}void Merge(const L_B &b) { // 把b这个线性基插入到当前这个线性基中.for (int i = 60 ; i >= 0 ; i --)if (b.d[i]) Insert(b.d[i]);}
}LB;int DFN[maxn];
int DFS_Clocks;
LL val[maxn];
VL CycleVal;inline void DFS(int u, int fa)
{DFN[u] = ++DFS_Clocks;vis[u] = true;for(int i=Head[u]; ~i; i=Edge[i].nxt){int v = Edge[i].v;if(v == fa) continue;if(vis[v] && DFN[v] < DFS_Clocks){///若当前当前点的时间戳大于出度点、则说明找到一条回路CycleVal.pb(val[v] ^ val[u] ^ Edge[i].w);}else if(!vis[v]){val[v] = val[u] ^ Edge[i].w;DFS(v, u);}}
}int main(void){__stTIME();__IOPUT();int nCase;sci(nCase);for(int Case=1; Case<=nCase; Case++){scii(n, m);EdgeInit();for(int i=1; i<=m; i++){int u, v;scii(u, v);LL w;scl(w);AddEdge(u, v, w);AddEdge(v, u, w);}CycleVal.clear();for(int i=0; i<=n; i++)vis[i] = false,val[i] = 0LL;DFS_Clocks = 0;for(int i=1; i<=n; i++)if(!vis[i])DFS(i, -1);LB.init();for(int i=0; i<(int)CycleVal.size(); i++)LB.Insert(CycleVal[i]);printf("Case #%d: %lld\n", Case, LB.query_max());}__enTIME();return 0;}void __stTIME()
{#if _TIMESTART = clock();#endif
}void __enTIME()
{#if _TIMEEND = clock();cerr<<"execute time = "<<(double)(END-START)/CLOCKS_PER_SEC<<endl;#endif
}void __IOPUT()
{#if _INPUTfreopen("in.txt", "r", stdin);#endif#if _OUTPUTfreopen("out.txt", "w", stdout);#endif
}