//scc代表 双联通分量  写习惯了 顺手就写成scc了也懒得改了 
#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<stack>
#include<queue>
#include<vector>
#define MAXM 2000100
#define MAX 200100
#define INF 0x7fffff
using namespace std;
int n,m,bridge,sum;
int low[MAX],dfn[MAX];
int head[MAX],ans,age;
int sccno[MAX];//代表当前点属于哪个双连通分量 
int dfsclock,scccnt;
vector<int>newmap[MAX];//储存缩点后的新图 
int instack[MAX];//标记当前点是否入栈 
int dis[MAX];//求树的直径时记录路径的长度 
int vis[MAX];//求树的直径时标记是否入队列 
stack<int>s;
struct node
{
	int beg,end,next;
}edge[MAXM];
void init()
{
	ans=0;
	bridge=0;
	memset(head,-1,sizeof(head));
}
void add(int u,int v)
{
    edge[ans].beg=u;
    edge[ans].end=v;
    edge[ans].next=head[u];
	head[u]=ans++;
}
void getmap()
{
	int a,b;
	while(m--)
	{
		scanf("%d%d",&a,&b);
		add(a,b);
		add(b,a);
	}
}
void tarjan(int u,int fa)
{
	int v,i;
	low[u]=dfn[u]=++dfsclock;
	instack[u]=1;
	s.push(u);
	int flag=1;
	for(i=head[u];i!=-1;i=edge[i].next)
	{
		v=edge[i].end;
		if(flag&&v==fa)//判重边 
		{
			flag=0;
			continue;
		}		    
		if(!dfn[v])
		{
			tarjan(v,u);
			low[u]=min(low[u],low[v]);
			if(dfn[u]<low[v])
				bridge++;
		}
		else if(instack[v])
		    low[u]=min(low[u],dfn[v]);
	}
    if(dfn[u]==low[u])
    {
    	scccnt++;
    	while(1)
    	{
    		v=s.top();
    		s.pop();
			instack[v]=0;
			sccno[v]=scccnt;
			if(v==u)
			break; 
    	}
    }
}
void find()
{
    int i;
	memset(low,0,sizeof(low));
	memset(sccno,0,sizeof(sccno));
	memset(dfn,0,sizeof(dfn));
	memset(instack,0,sizeof(instack));
	dfsclock=scccnt=0;
	for(i=1;i<=n;i++)
	{
		if(!dfn[i])
			tarjan(i,-1);
	}	
}
void suodian()
{
	int u,v,i,j;
	for(i=1;i<=scccnt;i++)
		newmap[i].clear();
	for(i=0;i<ans;i=i+2)
	{
		u=sccno[edge[i].beg];
		v=sccno[edge[i].end];
		if(u!=v)
		{
			newmap[u].push_back(v);
			newmap[v].push_back(u);
		}
	}
}
void bfs(int beg)
{
	queue<int>q;
	memset(dis,0,sizeof(dis));
	memset(vis,0,sizeof(vis));
	int i,j;
	while(!q.empty())
	    q.pop();
	sum=0;
	age=beg;
	vis[beg]=1;
	q.push(beg);
	int u;
	while(!q.empty())
	{
		u=q.front();
		q.pop();
		for(i=0;i<newmap[u].size();i++)
		{
			if(!vis[newmap[u][i]])
			{
				dis[newmap[u][i]]=dis[u]+1;
				vis[newmap[u][i]]=1;
				q.push(newmap[u][i]);
				if(sum<dis[newmap[u][i]])
				{
					sum=dis[newmap[u][i]];
					age=newmap[u][i];
				}
			}
		}
	}
}
void solve()
{
	int i,j;
	bfs(1);
	bfs(age);
	printf("%d\n",bridge-sum);
	//printf("%d\n%d\n",bridge,sum); 
}
int main()
{
	while(scanf("%d%d",&n,&m),n|m)
	{
		init();
		getmap();
		find();
		//printf("%d#\n",bridge);
		suodian();
		solve();
	}
	return 0;
}