#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>
#include <stack>
using namespace std;
#define mem(a) memset(a, 0, sizeof(a))
#define mem1(a) memset(a, -1, sizeof(a))
#define mem2(a) memset(a, 0x3f, sizeof(a))
#define fi first
#define se second
typedef pair<int, int> pll;
const int inf = 1061109567;
const int maxn = 2e5+5;
const int maxe = 1e6+5;
int head[maxn], head1[maxn], dis[maxn], num, num1, top, cnum, instack[maxn], st[maxn], dfn[maxn], low[maxn], s[maxn];
int maxx, pos, vis[maxe*2], cnt;
struct node
{
    int to, nextt;
}e[maxe*2], e1[maxe*2];
void add(int u, int v) {
    e[num].to = v, e[num].nextt = head[u], head[u] = num++;
}
void add1(int u, int v) {
    e1[num1].to = v, e1[num1].nextt = head1[u], head1[u] = num1++;
}
void init() {
    num = num1 = cnt = cnum = top = 0;
    mem1(head);
    mem(s);
    mem(vis);
    mem1(head1);
    mem(instack);
    mem(st);
    mem(dfn);
    mem(low);
    mem(dis);
}
pll edge[maxe];
void tarjan(int u) {
    instack[u] = 1;
    st[top++] = u;
    dfn[u] = low[u] = ++cnt;
    for(int i = head[u]; ~i; i = e[i].nextt) {
        int v = e[i].to;
        if(vis[i])
            continue;
        vis[i] = vis[i^1] = 1;
        if(!dfn[v]) {
            tarjan(v);
            low[u] = min(low[u], low[v]);
        } else if(instack[v]) {
            low[u] = min(low[u], dfn[v]);
        }
    }
    if(low[u] == dfn[u]) {
        ++cnum;
        int x;
        do {
            x = st[--top];
            instack[x] = 0;
            s[x] = cnum;
        } while(x != u);
    }
}
void bfs(int u) {
    queue <int> q;
    q.push(u);
    mem2(dis);
    dis[u] = 0;
    mem(vis);
    vis[u] = 1;
    maxx = 0, pos = u;
    while(!q.empty()) {
        int v = q.front(); q.pop();
        for(int i = head1[v]; ~i; i = e1[i].nextt) {
            int ve = e1[i].to;
            if(vis[ve])
                continue;
            vis[ve] = 1;
            dis[ve] = dis[v]+1;
            if(dis[ve]>maxx) {
                maxx = dis[ve];
                pos = ve;
            }
            q.push(ve);
        }
    }
}
int main()
{
    int n, m, x, y;
    while(cin>>n>>m) {
        if(n+m==0)
            break;
        init();
        for(int i = 0; i<m; i++) {
            scanf("%d%d", &x, &y);
            edge[i].fi = x, edge[i].se = y;
            add(x, y);
            add(y, x);
        }
        tarjan(1);
        int edgenum = 0;
        for(int i = 0; i<m; i++) {
            int x = edge[i].fi, y = edge[i].se;
            if(s[x]!=s[y]) {
                add1(s[x], s[y]);
                add1(s[y], s[x]);
                edgenum++;
            }
        }
        bfs(s[1]);
        bfs(pos);
        int ans = edgenum-maxx;
        printf("%d\n", ans);
    }
    return 0;
}