#include<cstdio>
#include<iostream>
#include<vector>
#include<cstring>
#include<algorithm>
#define MAX_N 5555
using namespace std;

vector<int> G[MAX_N];
bool vis[MAX_N];
int dfn[MAX_N],low[MAX_N],ind=0;

int cut[MAX_N];

int node;

void Tarjan(int u,int p){
    int child=0;
    dfn[u]=low[u]=++ind;
    vis[u]=1;
    for(int i=0;i<G[u].size();i++){
        int v=G[u][i];
        if(v==p||v==node)continue;
        if(!vis[v]){
            Tarjan(v,u);
            low[u]=min(low[v],low[u]);
            child++;
            if((p==-1&&child>1)||(p!=-1&&low[v]>=dfn[u]))
                cut[u]++;
        }
        else
            low[u]=min(dfn[v],low[u]);
    }
}

int n,m;

void init(){
    for(int i=0;i<=n;i++)G[i].clear();
    ind=0;
    memset(vis,0,sizeof(vis));
    memset(cut,0,sizeof(cut));
}

bool used[MAX_N];
int cu;
void dfs(int u,int p){
    if(u==p||used[u]||u==node||u==cu)return;
    used[u]=1;
    for(int i=0;i<G[u].size();i++)dfs(G[u][i],u);
}

int main(){
    while(scanf("%d%d",&n,&m)==2){
        int stab=1;
        init();
        int u,v;
        for(int i=0;i<m;i++) {
            scanf("%d%d", &u, &v);
            G[u].push_back(v);
            G[v].push_back(u);
        }
        for(int i=0;i<n;i++){
            node=i;
            memset(vis,0,sizeof(vis));
            ind=0;
            memset(cut,0,sizeof(cut));
            for(int j=0;j<n;j++)
                if((!vis[j])&&j!=node)
                    Tarjan(j,-1);
            int maxC=0;
            for(int j=0;j<n;j++)
                if(j!=node&&cut[j]>=maxC){
                    cu=j;
                    maxC=cut[j];
                }
            int ans=0;
            memset(used,0,sizeof(used));
            for(int j=0;j<n;j++)
                if((!used[j])&&j!=node&&j!=cu){
                    dfs(j,-1);
                    ans++;
                }
            stab=max(stab,ans);
        }
        printf("%d\n",stab);
    }

    return 0;
}