poj 2117 Electricity

/*
Tarjan求割点
*/
#include<iostream>
#include<cstdio>
#include<cstring>
#include<stack>
#define maxn 10010
using namespace std;
int n,m,num,head[maxn],low[maxn],dfn[maxn],f[maxn],father[maxn];
int point[maxn],topt,sum;
struct node{
    int v,pre;
}e[maxn*];
stack<int>s;
int init(){
    int x=;char s=getchar();
    while(s<''||s>'')s=getchar();
    while(s>=''&&s<=''){x=x*+s-'';s=getchar();}
    return x;
}
void Clear(){
    memset(head,-,sizeof(head));
    memset(low,,sizeof(low));
    memset(dfn,,sizeof(dfn));
    memset(f,,sizeof(f));
    memset(point,,sizeof(point));
    num=topt=sum=;
    while(!s.empty())s.pop();
}
void Add(int from,int to){
    e[num].v=to;
    e[num].pre=head[from];
    head[from]=num++;
}
void Tarjan(int x,int fa,int E){
    father[x]=fa;
    dfn[x]=low[x]=++topt;
    f[x]=;s.push(x);
    int sc=;
    for(int i=head[x];i!=-;i=e[i].pre){
        int v=e[i].v;
        if(i==(E^))continue;
        if(dfn[v]==){
            sc++;
            Tarjan(v,x,i);low[x]=min(low[x],low[v]);
            if(low[v]>=dfn[x])point[x]++;
        }
        else if(f[v])low[x]=min(low[x],dfn[v]);
    }
    if(fa<&&sc==)point[x]=;
    if(low[x]==dfn[x]){
        while(s.top()!=x){
            f[s.top()]=;s.pop();
        }
        f[s.top()]=;s.pop();
    }
}
void Init(){
    for(int i=;i<=m;i++){
        int u,v;
        u=init();v=init();
        u++;v++;
        Add(u,v);Add(v,u);
    }
    for(int i=;i<=n;i++)
        if(dfn[i]==){
            sum++;Tarjan(i,-,-);
        }
}
void Solve(){
    int mxx=-;
    for(int u=;u<=n;u++){
        if(father[u]==-){
            point[u]--;
        }
        mxx=max(mxx,point[u]);
    }
    printf("%d\n",sum+mxx);
}
int main()
{
    while(){
        n=init();m=init();
        if(n==&&m==)break;
        Clear();
        Init();
        Solve();
    }
}