1 //2017-08-27
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <iostream>
  5 #include <algorithm>
  6 #include <vector>
  7 #include <iomanip>
  8 #include <cmath>
  9 
 10 using namespace std;
 11 
 12 const int N = 5010;
 13 const int M = N*N;
 14 const double EPS = 1e-6;
 15 int head[N], rhead[N], tot, rtot;
 16 struct Edge{
 17     int to, next;
 18 }edge[M], redge[M];
 19 
 20 void init(){
 21     tot = 0;
 22     rtot = 0;
 23     memset(head, -1, sizeof(head));
 24     memset(rhead, -1, sizeof(rhead));
 25 }
 26 
 27 void add_edge(int u, int v){
 28     edge[tot].to = v;
 29     edge[tot].next = head[u];
 30     head[u] = tot++;
 31 
 32     redge[rtot].to = u;
 33     redge[rtot].next = rhead[v];
 34     rhead[v] = rtot++;
 35 }
 36 
 37 vector<int> vs;//后序遍历顺序的顶点列表
 38 bool vis[N];
 39 int cmp[N];//所属强连通分量的拓扑序
 40 
 41 //input: u 顶点
 42 //output: vs 后序遍历顺序的顶点列表
 43 void dfs(int u){
 44     vis[u] = true;
 45     for(int i = head[u]; i != -1; i = edge[i].next){
 46         int v = edge[i].to;
 47         if(!vis[v])
 48           dfs(v);
 49     }
 50     vs.push_back(u);
 51 }
 52 
 53 //input: u 顶点编号; k 拓扑序号
 54 //output: cmp[] 强连通分量拓扑序
 55 void rdfs(int u, int k){
 56     vis[u] = true;
 57     cmp[u] = k;
 58     for(int i = rhead[u]; i != -1; i = redge[i].next){
 59         int v = redge[i].to;
 60         if(!vis[v])
 61           rdfs(v, k);
 62     }
 63 }
 64 
 65 //Strongly Connected Component 强连通分量
 66 //input: n 顶点个数
 67 //output: k 强连通分量数;
 68 int scc(int n){
 69     memset(vis, 0, sizeof(vis));
 70     vs.clear();
 71     for(int u = 0; u < n; u++)
 72       if(!vis[u])
 73         dfs(u);
 74     int k = 0;
 75     memset(vis, 0, sizeof(vis));
 76     for(int i = vs.size()-1; i >= 0; i--)
 77       if(!vis[vs[i]])
 78         rdfs(vs[i], k++);
 79     return k;
 80 }
 81 
 82 int n, m;
 83 int a[10010], b[10010], c[10010];
 84 
 85 bool check(int len){
 86     init();
 87     for(int i = 0; i < len; i++){
 88         if(c[i] == 0){
 89             add_edge(a[i]+n, b[i]);
 90             add_edge(b[i]+n, a[i]);
 91         }else if(c[i] == 1){
 92             add_edge(a[i], b[i]);
 93             add_edge(a[i]+n, b[i]+n);
 94             add_edge(b[i], a[i]);
 95             add_edge(b[i]+n, a[i]+n);
 96         }else if(c[i] == 2){
 97             add_edge(a[i], b[i]+n);
 98             add_edge(b[i], a[i]+n);
 99         }
100     }
101     scc(n<<1);
102     for(int i = 0; i < n; i++)
103       if(cmp[i] == cmp[i+n])
104         return false;
105     return true;
106 }
107 
108 int main()
109 {
110     std::ios::sync_with_stdio(false);
111     //freopen("inputD.txt", "r", stdin);
112     int T;
113     cin>>T;
114     while(T--){
115         cin>>n>>m;
116         for(int i = 0; i < m; i++)
117           cin>>a[i]>>b[i]>>c[i];
118         int l = 0, r = m, mid, ans;
119         while(l <= r){
120             mid = (l+r)/2;
121             if(check(mid)){
122                 ans = mid;
123                 l = mid+1;
124             }else
125                   r = mid-1;
126         }
127         cout<<ans<<endl;
128     }
129 
130     return 0;
131 }