#include <time.h>

#include <stdlib.h>
#include <cstdint>
#include <cassert>
#include <algorithm>
#include <functional>
#include <iostream>
#include <limits>
#include <cstdint>
#include <cassert>
#include <algorithm>
#include <functional>
#include <iostream>
#include <limits>
#include <vector>
#include <map>
#include <set>
#include <iomanip>
#include <numeric>

using namespace std;
#include <cstdint>
#include <limits>
#include <vector>
#include <queue>
class Vertex;
class Edge{
public:
	friend class Vertex;
	friend class Graph;
	Vertex* from;
	Vertex* to;
	int64_t cost;
public:
	Edge(Vertex* from,Vertex* to,int64_t cost=0){
		this->from=from;
		this->to=to;
		this->cost=cost;
	}

};
struct Dijkstra{
	int64_t d;
	Vertex* parent;
	bool searched;
};

class Vertex{
	friend class Graph;
	std::vector<Edge*> departure;
	std::vector<Edge*> arrival;


public:
	Dijkstra dijk_data;
	int32_t id;
	bool count_finish=false;
	void add_edge(Edge* d){
		departure.push_back(d);
		d->to->arrival.push_back(d);
	}
	void initialize_Dijkstra(){
		dijk_data.d=std::numeric_limits<int64_t>::max();
		dijk_data.parent=NULL;
		dijk_data.searched=false;
		for(auto i=departure.begin();i!=departure.end();i++){
			Edge *temp=(*i);
			if(temp->to->dijk_data.d!=std::numeric_limits<int64_t>::max()||temp->to->dijk_data.parent!=NULL||temp->to->dijk_data.searched){
				temp->to->initialize_Dijkstra();
			}else{
			}
		}
	}
	int32_t count_union(Edge* e1,Edge* e2){
		int32_t retval=1;
		count_finish=true;
		for(auto i1=departure.begin();i1!=departure.end();i1++){
			Edge *temp=(*i1);
			if(temp==e1||temp==e2||temp->to->count_finish){
				continue;
			}
			retval+=temp->to->count_union(e1,e2);
		}
		return retval;
	}
};
class dijkstra_calc{
public:
	int64_t current_cost;
	Vertex* from;
	Vertex* to;
	dijkstra_calc(const int64_t cost, Vertex* c1,Vertex* c2):current_cost(cost),from(c1),to(c2){

	}
};
bool operator<(const dijkstra_calc& a,const dijkstra_calc& b){
	return a.current_cost<b.current_cost;
}
bool operator>(const dijkstra_calc& a,const dijkstra_calc& b){
	return a.current_cost>b.current_cost;
}


class Graph{
private:
	std::vector<Vertex*> v;
	std::vector<Edge*> e;
	static void dijkstra(Vertex* source,Vertex* goal=NULL){
		std::priority_queue<dijkstra_calc,std::vector<dijkstra_calc>,std::greater<dijkstra_calc> > queue;
		queue.push(dijkstra_calc(0,NULL,source));
		while(true){
			const dijkstra_calc temp=queue.top();
			queue.pop();
			if(!(temp.to->dijk_data.searched)){
				temp.to->dijk_data.searched=true;
				temp.to->dijk_data.parent=temp.from;
				temp.to->dijk_data.d=temp.current_cost;

				for(auto i=temp.to->departure.begin();i!=temp.to->departure.end();i++){
					const Edge *j=(*i);
					if(!j->to->dijk_data.searched){
						dijkstra_calc a(temp.current_cost+(j->cost),j->from,j->to);
						queue.push(a);
					}
				}
				if(temp.to==goal){
					return;
				}
			}
			if(queue.empty()){
				return;
			}
		}
	}
public:
	Graph(int32_t num_v){
		v.reserve(num_v);
		for(int32_t i1=0;i1<num_v;i1++){
			Vertex* temp=new Vertex();
			temp->id=i1;
			v.push_back(temp);
		}
	}
	void add_edge(int32_t from,int32_t to,int32_t cost=0){
		Edge *temp=new Edge(v[from-1],v[to-1],cost);
		e.push_back(temp);
		v[from-1]->add_edge(temp);
	}
	void dijkstra(int32_t start){
		v[start-1]->initialize_Dijkstra();
		dijkstra(v[start-1]);
	}
	void dijkstra(int32_t start,int32_t goal){
		v[start-1]->initialize_Dijkstra();
		dijkstra(v[start-1],v[goal-1]);
	}
	Vertex* getVertex(int place) const{
		return v[place-1];
	}
	bool isBridge(Edge* e1,Edge* e2){
		for(auto i1=v.begin();i1!=v.end();i1++){
			Vertex* temp=(*i1);
			temp->count_finish=false;
		}
		int32_t r=v[0]->count_union(e1,e2);
		return v.size()!=r;
	}
	vector<Edge*> getEdge(){
		return e;
	}
	virtual ~Graph(){
		for(auto i=v.begin();i!=v.end();i++){
			delete *i;
		}
		for(auto i=e.begin();i!=e.end();i++){
			delete *i;
		}
	}
};
int main() {
	int32_t n,m;
	cin>>n>>m;
	Graph g(n) ;
	for(int32_t i1=0;i1<m;i1++){
		int32_t a,b;
		cin>>a>>b;
		g.add_edge(a,b);
		g.add_edge(b,a);
	}
	int32_t ans=0;
	vector<Edge*> e=g.getEdge();
	for(int32_t i1=0;i1<m;i1++){
		if(g.isBridge(e.at(2*i1),e.at(2*i1+1))){
			ans++;
		}
	}
	cout<<ans<<endl;

}

Measured memory_bytes: 256