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#include <iomanip>
#include <iostream>
#include <utility>
#include <algorithm>

#include <cassert>
#include <string>
#include <vector>
#include <set>
#include <map>

#include "message.h"
#include "sabotaz.h"

using namespace std;

#define ALL(x) x.begin(), x.end()
#define VAR(a,b) __typeof (b) a = b
#define IN(a) int a; cin >> a
#define IN2(a,b) int a, b; cin >> a >> b
#define REP(i,n) for (int _n=(n), i=0; i<_n; ++i)
#define FOR(i,a,b) for (int _b=(b), i=(a); i<=_b; ++i)
#define FORD(i,a,b) for (int _b=(b), i=(a); i>=_b; --i)
#define FORE(i,a) for (VAR(i,a.begin ()); i!=a.end (); ++i) 
#define PB push_back
#define MP make_pair
#define ST first
#define ND second

typedef vector<int> VI;
typedef long long LL;
typedef pair<int,int> PII;
typedef double LD;

const int DBG = 0, INF = int(1e9);

int n, m;

struct edge {
  int target;
  int edge_id;
  edge(int target, int edge_id) : target(target), edge_id(edge_id) {}
};

const int INTS_LIMIT_PER_MSG = 10000;

void send_vector(int target, VI v) {
  while (v.size() > 0) {
    int to_send = min((int)v.size(), INTS_LIMIT_PER_MSG);
    PutInt(target, to_send);
    REP(i,to_send) {
      PutInt(target, v.back());
      v.pop_back();
    }
    Send(target);
  }
  PutInt(target, 0);
  Send(target);
}

void read_vector(int source, VI& res) {
  while (true) {
    Receive(source);
    int to_get = GetInt(source);
    if (to_get == 0) return;
    REP(i, to_get)
      res.PB(GetInt(source));
  }
}

set<int> cant_be_bridge;

void set_to_vector(const set<int>& s, VI& res) {
  res.reserve(s.size());
  FORE(it, s) res.PB(*it);
}

void send_data(int target, const VI& edges) {
  VI no_bridges;
  set_to_vector(cant_be_bridge, no_bridges);
  assert(no_bridges.size() <= edges.size());
  send_vector(target, edges);
  send_vector(target, no_bridges);
}

void get_data(int source, VI& edges) {
  read_vector(source, edges);
  VI no_bridges;
  read_vector(source, no_bridges);
  FORE(it, no_bridges) cant_be_bridge.insert(*it);
}

int my_id;

class find_bridges {

  void dfs(int node, int parent, VI& low, VI& pre_order, int& next_num, set<int>& tree_edges, const vector<vector<edge> >& v) {
    low[node] = pre_order[node] = next_num++;
    FORE(it, v[node]) if (it->target != parent) {
      if (pre_order[it->target] == -1) {
        tree_edges.insert(it->edge_id);
        dfs(it->target, node, low, pre_order, next_num, tree_edges, v);
        low[node] = min(low[node], low[it->target]);
        if (low[it->target] <= pre_order[node]) cant_be_bridge.insert(it->edge_id);
      }
      else
        low[node] = min(low[node], pre_order[it->target]);
    }
  }

  void do_find2(set<int>& tree_edges, const VI& all_nodes, const vector<vector<edge> >& v) {
    VI low(n), pre_order(n, -1);
    int next_num = 0;
    FORE(it, all_nodes)
      if (pre_order[*it] == -1)
        dfs(*it, -1, low, pre_order, next_num, tree_edges, v);
  }

  void do_find(set<int>& tree_edges, const VI& all_nodes, const vector<vector<edge> >& v) {
    assert(tree_edges.empty());
    VI pre_order(n, -1), parent(n), all_in_pre_order;
    {
      vector<PII> stck;
      int next_num = 0;
      FORE(it, all_nodes)
        if (pre_order[*it] == -1) {
          pre_order[*it] = next_num++;
          parent[*it] = -1;
          all_in_pre_order.PB(*it);
          stck.PB(MP(*it, 0));
          while (!stck.empty()) {
            int next = stck.back().first, edge_pos = stck.back().second;
            if (edge_pos == v[next].size()) {
              stck.pop_back();
              continue;
            }
            ++stck.back().second;
            int neigh = v[next][edge_pos].target;
            if (pre_order[neigh] == -1) {
              tree_edges.insert(v[next][edge_pos].edge_id);
              pre_order[neigh] = next_num++;
              parent[neigh] = *it;
              all_in_pre_order.PB(neigh);
              stck.PB(MP(neigh, 0));
            }
          }
        }
      reverse(ALL(all_in_pre_order));
      assert(all_in_pre_order.size() == all_nodes.size());
    }
    VI low(n);
    FORE(it, all_in_pre_order) {
      int a = *it;
      low[a] = pre_order[a];
      FORE(jt, v[a]) {
        int b = jt->target, edge_id = jt->edge_id;
        if (pre_order[b] < pre_order[a]) {
          if (parent[a] != b) low[a] = min(low[a], pre_order[b]);
        }
        else {
          if (low[b] <= pre_order[a]) cant_be_bridge.insert(edge_id);
          low[a] = min(low[a], low[b]);
        }
      }
    }
  }

  void purge_cant_be_bridge(const set<int>& tree_edges) {
    VI to_be_removed;
    FORE(it, cant_be_bridge)
      if (!tree_edges.count(*it)) to_be_removed.PB(*it);
    FORE(it, to_be_removed) cant_be_bridge.erase(*it);
  }

  public: 

  void process(VI& edges) {
    VI all_nodes;
    map<PII, int> edge_id;
    vector<vector<edge> > v(n);
    FORE(it, edges) {
      int e = *it;
      int a = BridgeEndA(e), b = BridgeEndB(e);
      if (a == b) continue;
      if (a > b) swap(a, b);
      PII p = MP(a, b);
      if (edge_id.count(p)) {
        cant_be_bridge.insert(edge_id[p]);
        continue;
      }
      edge_id[p] = e;
      if (v[a].empty())
        all_nodes.PB(a);
      v[a].PB(edge(b, e));
      if (v[b].empty())
        all_nodes.PB(b);
      v[b].PB(edge(a, e));
    }
    set<int> tree_edges;
    do_find2(tree_edges, all_nodes, v);
    purge_cant_be_bridge(tree_edges);
    edges.clear();
    set_to_vector(tree_edges, edges);
  }

  int count_bridges(const VI& tree_edges) {
    int res = 0;
    FORE(it, tree_edges)
      if (!cant_be_bridge.count(*it)) ++res;
    return res;
  }
};

int main() {
   ios_base::sync_with_stdio(0);
   cout.setf(ios::fixed);
   int machines_num = NumberOfNodes();
   my_id = MyNodeId();
   n = NumberOfIsles();
   m = NumberOfBridges();
   VI edges;
   for (int e = my_id; e < m; e += machines_num) edges.PB(e);
   find_bridges f;
   f.process(edges);
   for (int multiplier = 1, cur_id = my_id; ; multiplier *= 2, cur_id /= 2) {
     if (cur_id % 2 == 1) {
       int sibling = (cur_id - 1) * multiplier;
       send_data(sibling, edges);
       return 0;
     }
     int sibling = (cur_id + 1) * multiplier;
     if (sibling >= machines_num) {
       if (cur_id == 0) break;
       else continue;
     }
     get_data(sibling, edges);
     f.process(edges);
   }
   assert(my_id == 0);
   cout << f.count_bridges(edges) << endl;
   return 0;
}