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

#define N 5005
#define M 10005

int n,m;
struct edge{int v,next;edge(){}edge(int v,int next):v(v),next(next){}}edgs[M<<2];
int head[N],idx=1;
int dfn[N],low[N],dfnn;
bool kill[M<<1];
int from[N],dcc;
int dcc_head[N];
bool vis[N],vis2[N];
int in[N];

inline void add(int u,int v){edgs[++idx]={v,head[u]};head[u]=idx;}
inline void dcc_add(int u,int v){edgs[++idx]={v,dcc_head[u]};dcc_head[u]=idx;}

void tarjan(int u,int fa)
{
	dfn[u]=low[u]=++dfnn;
	bool flag=1;
	for(int edg=head[u];edg;edg=edgs[edg].next)
	{
		int v=edgs[edg].v;
		if(dfn[v])
		{
			if(v==fa&&flag)
				flag=0;
			else low[u]=min(low[u],dfn[v]);
		}
		else
		{
			tarjan(v,u);
			low[u]=min(low[u],dfn[v]);
			if(dfn[u]<low[v])
				kill[edg]=kill[edg^1]=1;
		}
	}
}

void dfs(int u,int fromm)
{
	vis[u]=1;
	from[u]=fromm;
	for(int edg=head[u];edg;edg=edgs[edg].next)
	{
		int v=edgs[edg].v;
		if(kill[edg])
		{
			dcc_add(from[u],v);
			continue;
		}
		if(vis[v])
			continue;
		dfs(v,fromm);
	}
}

signed main()
{
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;++i)
	{
		int u,v;
		scanf("%d%d",&u,&v);
		if(u==v)
			continue;
		add(u,v);add(v,u);
	}
	for(int i=1;i<=n;++i)
		if(!dfn[i])
			tarjan(i,0);
	for(int i=1;i<=n;++i)
		if(!vis[i])
			dfs(i,++dcc);
	for(int i=1;i<=dcc;++i)
	{
		memset(vis2,0,sizeof vis2);//vis2[i]=1;
		for(int edg=dcc_head[i];edg;edg=edgs[edg].next)
		{
			int v=from[edgs[edg].v];
			in[v]+=1-vis2[v];
			vis2[v]=1;
		}
	}
	int cnt=0;
	for(int i=1;i<=dcc;++i)
		cnt+=(in[i]==1);
	printf("%d",(cnt+1>>1));
	return 0;
}