#include <iostream>

#include <cstdio>

#include <cstring>

#include <queue>

#include <algorithm>

#include <vector>

#include <stack>

#define mem(a, b) memset(a, b, sizeof(a))

using namespace std;

const int maxn = , INF = 0x7fffffff;

int pre[maxn], low[maxn], sccno[maxn], d[maxn], head[maxn], vis[maxn*];

int dfs_clock, n, m, scc_cnt, bridge, maxway, pos;

stack<int> S;

int cnt1, cnt2;

struct edge

{

    int u, v, next;

}Edge1[maxn*],Edge2[maxn*];

void add1(int u, int v)

{

    Edge1[cnt1].u = u;

    Edge1[cnt1].v = v;

    Edge1[cnt1].next = head[u];

    head[u] = cnt1++;

}

void add2(int u, int v)

{

    Edge2[cnt2].u = u;

    Edge2[cnt2].v = v;

    Edge2[cnt2].next = head[u];

    head[u] = cnt2++;

}

void init()

{

    dfs_clock = ;

    scc_cnt = ;

    cnt1 = cnt2 = ;

    bridge = ;

    mem(pre, );

    mem(vis, );

    mem(low, );

    mem(head, -);

    mem(sccno, );

}

void tarjan(int u)

{

    pre[u] = low[u] = ++dfs_clock;

    S.push(u);

    for(int i=head[u]; i != -; i=Edge1[i].next)

    {

        int v = Edge1[i].v;

        if(vis[i]) continue;

        vis[i] = vis[i^] = ;  //  标记同向边和反向边

        if(!pre[v])

        {

            tarjan(v);

            low[u] = min(low[v], low[u]);

        }

        else if(!sccno[v])

            low[u] = min(low[u], pre[v]);

    }

    if(low[u] == pre[u])

    {

        scc_cnt++;

        for(;;)

        {

            int x = S.top(); S.pop();

            sccno[x] = scc_cnt;

            if(x == u) break;

        }

    }

}

void bfs(int u)

{

    queue<int> Q;

    mem(d, );

    mem(vis, );

    Q.push(u);

    d[u] = ;

    vis[u] = ;

    maxway = , pos = u;

    while(!Q.empty())

    {

        u = Q.front(); Q.pop();

        for(int i=head[u]; i != -; i=Edge2[i].next)

        {

            int v = Edge2[i].v;

            if(vis[v]) continue;

            vis[v] = ;

            d[v] = d[u] + ;

            if(d[v] > maxway)

                maxway = d[v], pos = v;

            Q.push(v);

        }

    }

}

int main()

{

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

    {

        init();

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

        {

            int u, v;

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

            add1(u, v);

            add1(v, u);

        }

        tarjan();

        mem(head, -);

        for(int i=;i < cnt1; i+=)  //以连通分量建图  顺便求桥的数量

            if(sccno[Edge1[i].u] != sccno[Edge1[i].v])

            {

                add2(sccno[Edge1[i].u], sccno[Edge1[i].v]);

                add2(sccno[Edge1[i].v], sccno[Edge1[i].u]);

                bridge++;

            }

        bfs(sccno[]);

        bfs(pos);

        printf("%d\n",bridge - maxway);

    }

    return ;

}