#include <algorithm>

 #include <cstring>

 #include <cstdio>

 using namespace std;

 const int N();

 int n,m,u,v;

 int sumedge,head[N<<];

 struct Edge

 {

     int to,next;

     Edge(int to=,int next=) :

         to(to),next(next) {}

 }edge[N*];

 void ins(int from,int to)

 {

     edge[++sumedge]=Edge(to,head[from]);

     head[from]=sumedge;

 }

 int low[N<<],dfn[N<<],tim;

 int sumcol,num[N];

 int cutpoint[N];

 void DFS(int now,int pre)

 {

     low[now]=dfn[now]=++tim;

     int sumtredge=,if_cutpoint=;

     for(int i=head[now];i!=-;i=edge[i].next)

     {

         int go=edge[i].to;

         if((i^)!=pre)

         {

             if(!dfn[go])

             {

                 sumtredge++;

                 DFS(go,i);

                 if(low[go]>=dfn[now])

                 {

                     if_cutpoint=;

                     num[now]++;

                 }

                 low[now]=min(low[now],low[go]);

             }

             else low[now]=min(low[now],dfn[go]);

         }

     }

     if(pre==-)

     {

         if(sumtredge>)  cutpoint[now]=;

     }

     else if(if_cutpoint) cutpoint[now]=;

 }

 int ans,cnt,tmp,vis[N],root[N],cut[N];

 void link(int x)

 {

     vis[x]=;

     for(int i=head[x];i!=-;i=edge[i].next)

     {

         v=edge[i].to;

         if(!vis[v]) link(v);

     }

 }

 void cut_point(int pre,int fa)

 {

     vis[pre]=;

     for(int i=head[pre];i!=-;i=edge[i].next)

     {

         int go=edge[i].to;

         if(!vis[go])

         {

             if(pre==fa) cnt++;

             cut_point(go,fa);

         }

     }

 }

 void init(int n)

 {

     sumedge=-; ans=tim=tmp=cnt=;

     memset(vis,,sizeof(vis));

     memset(low,,sizeof(low));

     memset(dfn,,sizeof(dfn));

     memset(num,,sizeof(num));

     memset(cut,,sizeof(cut));

     memset(root,,sizeof(root));

     memset(head,-,sizeof(head));

     memset(cutpoint,,sizeof(cutpoint));

 }

 int main()

 {

 //    freopen("makerout.txt","r",stdin);

 //    freopen("myout.txt","w",stdout);

     while(~scanf("%d%d",&n,&m)&&n)

     {

         init(n);

         if(m==) printf("%d\n",n-);

         else

         {

             for(;m;m--)

             {

                 scanf("%d%d",&u,&v);

                 ins(u,v); ins(v,u);

             }

             for(int i=;i<n;i++)

                 if(!vis[i]) ++tmp,link(i);

             for(int i=;i<n;i++)

                 if(!dfn[i]) DFS(i,-);

             for(int i=;i<n;i++)

                 if(cutpoint[i])

                 {

                     memset(vis,,sizeof(vis));

                     cut_point(i,i);

                     ans=max(ans,cnt-);

                     cnt=;

                 }

             ans+=tmp;

             printf("%d\n",ans);

         }

     }

     return ;

 }