#include <bits/stdc++.h>
using namespace std;
#define forr(i, a, b) for(int i = (a); i < (int)(b); i++)
#define forn(i, n) forr(i, 0, n)
#define forall(it, v) for(auto it = v.begin(); it != v.end(); ++it)
#define dforn(i, n) for(int i = n - 1; i >= 0; i--)
#define db(v) cerr << #v << " = " << v << endl
#define pb push_back
typedef long long ll;
const int MAXN = 20050;

int tc, n, m, nCC, color[MAXN];
vector<int> G[MAXN], H[MAXN], topsort, CC[MAXN];
set<int> ADY[MAXN];
bool used[MAXN], contado[MAXN];

void limpiar(){
  forn(i, MAXN){
    G[i].clear();
    H[i].clear();
    CC[i].clear();
    ADY[i].clear();
  }
  nCC = 0;
  topsort.clear();
  memset(contado, false, sizeof contado);
  memset(color, 0, sizeof color);
  memset(used, false, sizeof used);
}

void dfs(int v, int p){
  used[v] = true;
  forn(i, G[v].size()){
    int w = G[v][i];
    if(w == p) continue;
    if(used[w]) continue;
    dfs(w, v);
  }
  topsort.push_back(v);
}

void dfs_reverse(int v, int p, int c){
  //~ printf("Visitando %d con color %d\n", v + 1, c + 1);
  used[v] = true;
  color[v] = c;
  CC[c].push_back(v);
  forn(i, H[v].size()){
    int w = H[v][i];
    if(w == p) continue;
    if(used[w]) continue;
    dfs_reverse(w, v, c);
  }
}

int main() {
  scanf("%d", &tc);
  while(tc--){
    limpiar();
    scanf("%d %d", &n, &m);
    forn(i, m){
      int a, b;
      scanf("%d %d", &a, &b);
      --a; --b;
      G[a].pb(b);
      H[b].pb(a);
    }
    forn(i, n){
      if(!used[i]){
        dfs(i, -1);
      }
    }
    reverse(topsort.begin(), topsort.end());
    memset(used, false, sizeof used);
    forn(i, topsort.size()){
      int v = topsort[i];
      if(!used[v]){
        dfs_reverse(v, -1, nCC++);
      }
    }

    forn(i, nCC){
      printf("CC %d\n", i + 1);
      forn(j, CC[i].size()){
        printf("%d ", CC[i][j] + 1);
      }
      puts("");
    }

    forn(i, nCC){
      forn(j, CC[i].size()){
        int v = CC[i][j];
        forn(k, G[v].size()){
          int to = G[v][k];
          if(to == i) continue;
          ADY[i].insert( color[to] );
        }
      }
    }

    int ans = nCC;
    forn(i, nCC){
      printf("Desde CC %d:\n", i + 1);
      forall(it, ADY[i]){
        int to = *it;
        printf(" --> %d\n", to);
        if(!contado[to]){
          contado[to] = true;
          ans--;
        }
      }
    }

    printf("%d\n", ans);
  }
  return 0;
}