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#pragma comment(linker, "/STACK:102400000,102400000")
#include <stdio.h>
#include <vector>
#include <algorithm>
#include <string.h>
#include <queue>
#include <stack>
using namespace std;
const int maxn = 200005;
int n,m, id, low[maxn], timestamp[maxn], t, cnt, res, ebccnum, belong[maxn];
struct Edge
{
int to, id;
Edge(int to, int id):to(to),id(id){}
};
vector<Edge> g[maxn];
typedef vector<Edge>::iterator vit;
stack<int> s;
void dfs(int cur, int fa)
{
timestamp[cur] = low[cur] = ++t;
s.push(cur);
for (vit x = g[cur].begin(); x!=g[cur].end(); x++)
{
if (!timestamp[x->to])
{
dfs(x->to, x->id);
low[cur] = min(low[cur], low[x->to]);
if (low[x->to]>timestamp[cur])
{
cnt++;
ebccnum++;
int j;
do
{
j = s.top();
s.pop();
belong[j] = ebccnum;
} while (j!=x->to);
}
}
else if (x->id!=fa)
{
low[cur] = min(low[cur], timestamp[x->to]);
}
}
}
int head[maxn],num;
struct Arc
{
int from, to, nxt;
}gg[2000005];
void addArc(int a, int b)
{
gg[num].from = a, gg[num].to = b, gg[num].nxt = head[a];
head[a] = num++;
}
bool v[maxn];
int bfs(int i, int &ans)
{
memset(v, 0, sizeof(v));
ans = 0;
int p;
struct Node
{
int to, dis;
Node(int to, int dis):to(to),dis(dis){}
};
queue<Node> q;
q.push(Node(i,0));
v[i] = true;
while(!q.empty())
{
Node front = q.front();
q.pop();
if (ans<front.dis)
{
ans = front.dis;
p = front.to;
}
for (int h = head[front.to],to; ~h; h = gg[h].nxt)
{
to = gg[h].to;
if (!v[to])
{
v[to] = true;
q.push(Node(to, front.dis+1));
}
}
}
return p;
}
void rebuild()
{
memset(head, -1, sizeof(head));
num = 0;
for (int i = 1; i<=n;i++)
{
for (vit x = g[i].begin(); x!=g[i].end(); x++)
{
if (belong[i]!=belong[x->to])
{
addArc(belong[i], belong[x->to]);
}
}
}
}
int main() {
#ifdef LOCAL
freopen("d:\\data.in", "r", stdin);
#endif
while(scanf("%d%d", &n,&m),n||m)
{
id = t = cnt = 0;
memset(low,0, sizeof(low));
memset(timestamp, 0, sizeof(timestamp));
for (int i = 1; i<=n;i++)
{
g[i].clear();
}
while(m--)
{
int a,b;
scanf("%d%d", &a, &b);
id++;
g[a].push_back(Edge(b,id)), g[b].push_back(Edge(a, id));
}
ebccnum = 0;
while(!s.empty())
{
s.pop();
}
memset(belong, 0, sizeof(belong));
dfs(1,0);
if (!ebccnum)
{
puts("0");
continue;
}
ebccnum++;
for (int i = 1; i<=n;i++)
{
if (!belong[i])
{
belong[i] = ebccnum;
}
}
rebuild();
int ans;
int p = bfs(1, ans);
bfs(p, ans);
printf("%d\n", cnt-ans);
}
return 0;
}
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