#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<queue>
#include<stack>
#include<algorithm>
#include<vector>
using namespace std;
const int N=3e5+9;
const int M=6e5+9;
struct node{
    int last;
    int to;
}e[M],e2[M];
int head[N],head2[N];
int cnt,cnt2;
int vis[N];
int dfn[N],low[N];
int c[N],poi;
bool bridge[M];
int n,m,dcc;
void add(int from,int to)
{
    e[++cnt].last=head[from];
    e[cnt].to=to;
    head[from]=cnt;
}
void add2(int from,int to)
{
    e2[++cnt2].last=head2[from];
    e2[cnt2].to=to;
    head2[from]=cnt2;
}
void tarjan(int u,int edge)
{
    low[u]=dfn[u]=++poi;
    for(int i=head[u];i;i=e[i].last)
    {
        int v=e[i].to;
        if(!dfn[v])
        {
            tarjan(v,i);
            low[u]=min(low[u],low[v]);
            if(low[v]>dfn[u]) bridge[i]=bridge[i^1]=1;
        }
        else if(i!=(edge^1)) low[u]=min(low[u],dfn[v]);
    }
}
void dfs(int x)
{
    c[x]=dcc;
    for(int i=head[x];i;i=e[i].last)
    {
        int v=e[i].to;
        if(c[v]||bridge[i]) continue;
        dfs(v);
    }
}
int maxdep,maxw;
void dfs2(int dep,int x,int fa)
{
    cout<<dep<<endl;
    if(dep>maxdep)
    {
        maxw=x;
        maxdep=dep;
    }
    for(int i=head2[x];i;i=e2[i].last)
    {
        int v=e2[i].to;
        if(v!=fa)
            dfs2(dep+1,v,x);
    }
}
int main()
{
    scanf("%d%d",&n,&m);
    cnt=1,cnt2=1;
    for(int i=1;i<=m;i++)
    {
        int u,v;
        scanf("%d%d",&u,&v);
        add(u,v);
        add(v,u);
    }
    for(int i=1;i<=n;i++)
        if(!dfn[i]) tarjan(i,0);//缩点，找遍双
    for(int i=1;i<=n;i++)
    {
        if(!c[i])
        {
            ++dcc;
            dfs(i);
        }
    }//缩点
    for(int i=2;i<=cnt;i++)
    {
        int x=e[i^1].to;
        int y=e[i].to;
        if(c[i]==c[y]) continue;
        add2(c[x],c[y]); 
    }
    dfs2(0,1,0);
    dfs2(0,maxw,0);
    cout<<maxdep<<endl;
    return 0; 
}