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#include<cstdio>
#include<algorithm>
#include<utility>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<cmath>
#include<iostream>

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

#define FORE(c, a, b) for(int c=a; c<= int(b); ++c)
#define FORD(c, a, b) for(int c=a; c>= int(b); --c)
#define FORIT(it, cont, cont_t) for(cont_t::iterator it = cont.begin(); it != cont.end(); ++it)
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define ALL(a) a.begin(), a.end() 
#define PR(n) printf("%d ", (int) (n)) 
#define PRL(n) printf("%lld ", (ll) (n)) 
#define SC(n) scanf("%d ", &n) 

#define xx first
#define yy second
#define pb push_back
#define mp make_pair
#define itr iterator

#define dbg if(0)
#define prd dbg printf("%d: ", id); dbg printf

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned int uint;

typedef vector<int> vi;
typedef set<int> si;
typedef map<int, int> mi;
typedef pair<int, int> pi;
typedef vector<pi> vpi;
typedef vector<vi> vvi;
typedef vector<vpi> vvpi;

const int NMAX = 1000*1000+9;

int id, nd, nn;

vvi scanEdgesLists() {
	vvi out(nn);
	for(int i = id; i < NumberOfBridges(); i += nd) {
		int x = BridgeEndA(i), y = BridgeEndB(i);
		out[x].pb(y); out[y].pb(x);
	}
	return out;
}

vvi receiveEdgesLists(int sender, vvi &out) {
	prd("receives msg from %d: \n", sender);
	Receive(sender);
	int msgSize = GetInt(sender);
	REP(i, msgSize) {
		int x = GetInt(sender), y = GetInt(sender);
		out[x].pb(y); out[y].pb(x);
	}
	return out;
}	

void sendMsg(int node, vi & msg) {
	prd("sending msg to %d: \n", node);
	PutInt(node, msg.size() / 2);
	FORIT(it, msg, vi) {
		PutInt(node, *it);
		dbg printf("%d ", *it);
	}
	dbg printf("\n");
	Send(node);
}

class Forest {
public:
	vvpi tree;
	vi low, level, msg;
	vvi blocks;

	void dfs(int v, int forb, vvi & edges) {
		prd("dfs %d level = %d\n", v, level[v]);
		FORIT(it, edges[v], vi) {
			int w = *it;
			if(w == forb) {
				forb = -1;
				continue;
			}
			if(level[w]) {
				prd("dfs %d see %d\n", v, level[w]);
				low[v] = min(low[v], level[w]);
			}
			else {
				low[w] = level[w] = level[v] + 1;
				dfs(w, v, edges);
				low[v] = min(low[v], low[w]);
				tree[v].pb(mp(w, (low[w] == level[w])));
			}
		}
	}
	
	void walkTree(int v, int head) {
		prd("walkTree %d head = %d\n", v, head);
		blocks[head].pb(v);
		FORIT(it, tree[v], vpi) {
			if(it->yy) {
				msg.pb(v); msg.pb(it->xx);
				walkTree(it->xx, it->xx);
			}
			else
				walkTree(it->xx, head);
		}
	}
	
	Forest(vvi & edges) {
		prd("Creating Forest\n");
		tree = vvpi(nn);
		low = vi(nn);
		level = vi(nn);
		blocks = vvi(nn);
		
		REP(i, nn)
			if(!level[i]) {
				low[i] = level[i] = 1;
				dfs(i, -1, edges);
			}
			
		REP(i, nn)
			if(level[i] == 1)
				walkTree(i, i);
				
		REP(i, nn) {
			dbg {
				prd("block: ");
				FORIT(it, blocks[i], vi)
					printf("%d ", *it);
				printf("\n");
			}
			if(blocks[i].size() > 1) {
				msg.pb(blocks[i][0]); msg.pb(blocks[i].back());
				REP(j, blocks[i].size() - 1) {
					msg.pb(blocks[i][j]); msg.pb(blocks[i][j+1]);
				}
			}
		}
	}
	
	vvi retrieveEdges() {
		vvi out(nn);
		for(int i = 0; i < msg.size(); i += 2) {
			int x = msg[i], y  = msg[i+1];
			out[x].pb(y); out[y].pb(x);
		}
		return out;
	}
	
	int getNumberOfBridges() {
		int ans = 0;
		REP(i, nn)
			FORIT(it, tree[i], vpi)
				ans += it->yy;
		return ans;
	}
};

int main() {
	id = MyNodeId(); nn = NumberOfIsles(); nd = NumberOfNodes();
	vvi edges = scanEdgesLists();
	Forest forest(edges);
	int turn = 1;
	
	while(1) {
		if(id % (2*turn)) {
			sendMsg(id - turn, forest.msg);
			break;
		}
		else {
			int next = id + turn;
			turn *= 2;
			if(next >= nd) {
				if(id == 0)
					break;
				else
					continue;
			}
			edges = forest.retrieveEdges();
			receiveEdgesLists(next, edges);
			forest = Forest(edges);
		}
	}
	
	if(id == 0)
		printf("%d", forest.getNumberOfBridges());
	return 0;
}