#include<cstdio>
#include<cstring>
#include<stack>
#include<algorithm>
using namespace std;

#define DOTMAX 5001
#define EDGEMAX 10001
#define min(a,b) ( (a)<(b)?(a):(b) )

stack<int>sta;
struct node
{
    int t;
    node *next;
}dotset[EDGEMAX*2];
node hash[DOTMAX];
int visit[DOTMAX];
int low[DOTMAX];
int ID[DOTMAX];
int dfsn[DOTMAX];

int cont=0;
node *Newnode()
{
    node *p;
    p=&dotset[cont];
    cont++;
    return p;
}
void init(int n)
{
	while(!sta.empty())
	{

		sta.pop();
	}
	cont=0;
    int i;
    for(i=0;i<=n;i++)
    {
        hash[i].next=NULL;
        hash[i].t=-1;
    }
}
bool check(int a,int b)
{

	node *p;
	for(p=hash[a].next;p!=NULL;p=p->next)
	{

		if(p->t==b)
			return false;
	}
	return true;
}

void AddNode(int a,int b)
{
	node *p;
	node *q;

	if(check(a,b))
	{
		q=&hash[a];
		p=Newnode();
		p->t=b;
		p->next=q->next;
		q->next=p;

		q=&hash[b];
		p=Newnode();
		p->t=a;
		p->next=q->next;
		q->next=p;


	}
}
int gcc=0;
int cnt=0;
void dfs(int u,int father)
{
	++cnt;
	dfsn[u]=cnt;low[u]=cnt;visit[u]=1;
	sta.push(u);
	node *p;
	for(p=hash[u].next;p!=NULL;p=p->next)
	{

		int v=p->t;
		if(v==father)
			continue;
		if(!visit[v])
		{
			dfs(v,u);
			low[u]=min(low[u],low[v]);
			if(low[v]<=dfsn[u])
				return ;
			if(low[v]>dfsn[u])
			{
				gcc++;
				while(sta.top()!=p->t)
				{
					ID[sta.top()]=gcc;
					sta.pop();
				}
			}
			ID[p->t]=gcc;
			sta.pop();
		}
		else if(u!=v)
		{
			low[u]=min(low[u],dfsn[v]);
		}
	}


}

int main()
{

	int n,m;
	int a,b;
	int i;
	scanf("%d%d",&n,&m);

		init(n);
		memset(low,0,sizeof(low));
		memset(ID,0,sizeof(ID));
		memset(visit,0,sizeof(visit));
		gcc=0;
		cnt=0;
		AddNode(0,1);
		
		for(i=1;i<=m;i++)
		{

			scanf("%d%d",&a,&b);
			AddNode(a,b);
		}

		int degree[DOTMAX];
		memset(degree,0,sizeof(degree));
		dfs(0,-1);
		int res=0;
		node *p;
		for(i=1;i<=n;i++)
		{
			for(p=hash[i].next;p!=NULL;p=p->next)
			{

				if(ID[i]!=ID[p->t]&&p->t!=0)
					degree[ID[i]]++;
			}
		}
		for(i=1;i<=gcc;i++)
		{
			if(degree[i]==1)
				res++;
		}
		printf("%d\n",(res+1)/2);
	
	return 0;

}