#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<string>
#include<algorithm>
#include<queue>
#include<vector>
#include<set>
#include<stack>
using namespace std;
vector<int> e[200005],mp[200005];
int n,m,use[200005],top,newflag,Dfs[200005],low[200005],isstack[200005];
int dp[200005],vis[200005],ans,bridge;
stack<int> s;
void init()
{
    ans=0,bridge=0;
    memset(use,0,sizeof(use));
    memset(Dfs,0,sizeof(Dfs));
    memset(low,0,sizeof(low));
    memset(isstack,0,sizeof(isstack));
    top=newflag=0;
    while(!s.empty())
        s.pop();
    for(int i=1;i<=n;i++)
        e[i].clear(),mp[i].clear();
}
int bfs(int x)
{
    int pos;
    pos=x;
    memset(vis,0,sizeof(vis));
    memset(dp,0,sizeof(dp));
    queue<int> q;
    q.push(x);
    vis[x]=1;
    while(!q.empty())
    {
        int u=q.front();
        q.pop();
        for(int i=0;i<mp[u].size();i++)
        {
            int v=mp[u][i];
            if(vis[v]) continue;
            vis[v]=1;
            dp[v]=dp[u]+1;
            q.push(v);
            if(dp[v]>ans)
            {
                ans=dp[v];
                pos=v;
            }
        }
    }
    return pos;
}
void tarjan(int u,int father)
{
    Dfs[u]=low[u]=++top;
    s.push(u);
    isstack[u]=1;
    int cnt=0;
    for(int i=0;i<e[u].size();i++)
    {
        int v=e[u][i];
        if(!Dfs[v])
        {
            tarjan(v,u);
            low[u]=min(low[u],low[v]);
            if(low[v]>Dfs[u])
                bridge++;
        }
        else if(v==father)
        {
            if(cnt) low[u]=min(low[u],Dfs[v]);
            cnt++;
        }
        else if(isstack[v])
            low[u]=min(low[u],Dfs[v]);
    }
    if(low[u]==Dfs[u])
    {
        newflag++;
        int x;
        do
        {
            x=s.top();
            s.pop();
            isstack[x]=0;
            use[x]=newflag;
        }while(x!=u);
    }
}
int main()
{
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        if(n==0&&m==0)
            break;
        init();
        for(int i=1;i<=m;i++)
        {
            int x,y;
            scanf("%d%d",&x,&y);
            e[x].push_back(y);
            e[y].push_back(x);
        }
        for(int i=1;i<=n;i++)
        {
            if(!Dfs[i])
                tarjan(i,-1);
        }
        for(int i=1;i<=n;i++)
        {
            for(int j=0;j<e[i].size();j++)
            {
                int u,v;
                u=i,v=e[i][j];
                if(use[u]!=use[v])
                    mp[use[u]].push_back(use[v]);
            }
        }
        bfs(bfs(1));
        printf("%d\n",bridge-ans);
    }
    return 0;
}