1 #include <stdio.h>
  2 #include <iostream>
  3 #include <algorithm>
  4 #include <string.h>
  5 #include <queue>
  6 #include <vector>
  7 using namespace std;
  8 
  9 const int MAXN = 200010;
 10 const int MAXM = 1000015;
 11 struct Edge
 12 {
 13     int to,from,next;
 14 }edge[MAXM*2],eedge[MAXM*2];
 15 int head[MAXN],edge_cnt;
 16 int Low[MAXN],DFN[MAXN],Stack[MAXN],Belong[MAXN];//Belong数组的值是1~block
 17 int Index,top;
 18 int block;
 19 bool Instack[MAXN];
 20 int bridge;    
 21 int n,m;
 22 int key,d,vis[MAXN];
 23 void addedge(int u,int v)
 24 {
 25     edge[edge_cnt].from=u;
 26     edge[edge_cnt].to = v;edge[edge_cnt].next = head[u];
 27     head[u] = edge_cnt++;
 28 }
 29 void addedge2(int u,int v)
 30 {
 31     eedge[edge_cnt].from=u;
 32     eedge[edge_cnt].to = v;eedge[edge_cnt].next = head[u];
 33     head[u] = edge_cnt++;
 34 }
 35 void Tarjan(int u,int id)
 36 {
 37     int v;
 38     Low[u] = DFN[u] = ++Index;
 39     Stack[top++] = u;
 40     Instack[u] = true;
 41     for(int i = head[u];i != -1;i = edge[i].next)
 42     {
 43         v = edge[i].to;
 44         if( i == (id^1))continue;
 45         if( !DFN[v] )
 46         {
 47             Tarjan(v,i);
 48             if(Low[u] > Low[v])Low[u] = Low[v];
 49             if(Low[v] > DFN[u])
 50             {
 51                 bridge++;
 52             }
 53         }
 54         else if(Instack[v] && Low[u] > DFN[v])
 55              Low[u] = DFN[v];
 56     }
 57     if(Low[u] == DFN[u])
 58     {
 59         block++;
 60         do
 61         {
 62             v = Stack[--top];
 63             Instack[v] = false;
 64             Belong[v] = block;
 65         }
 66         while( v != u );
 67     }
 68 }
 69 void dfs(int u,int len)
 70 {
 71     vis[u]=1;
 72     if(len > d)
 73     {
 74         d=len;
 75         key=u;
 76     }
 77     for(int i = head[u]; i != -1 ; i=eedge[i].next)
 78     {
 79         int v=eedge[i].to;
 80         if(!vis[v])
 81         {
 82             dfs(v,len+1);
 83         }
 84     }
 85     return;
 86 }
 87 void init()
 88 {
 89     edge_cnt=0;
 90     memset(head,-1,sizeof(head));
 91 }
 92 void solve()
 93 {
 94     memset(DFN,0,sizeof(DFN));
 95     memset(Low,0,sizeof(Low));
 96     memset(Belong,0,sizeof(Belong));
 97     memset(Instack,false,sizeof(Instack));
 98     Index = top = block = bridge = 0;
 99     Tarjan(1,-1);
100     int orz=edge_cnt;
101     edge_cnt=0;
102     memset(head,-1,sizeof(head));
103     for(int i = 0 ; i < orz ; i++)
104     { 
105         if(Belong[edge[i].to]!=Belong[edge[i].from])
106         {
107             
108             addedge2(Belong[edge[i].to],Belong[edge[i].from]);
109             addedge2(Belong[edge[i].from],Belong[edge[i].to]);
110         }
111     }
112     d=0;    key=0;
113     memset(vis,0,sizeof(vis));
114     dfs(1,0);
115     d=0;//    cout << key <<endl;
116     memset(vis,0,sizeof(vis));
117     dfs(key,0);
118 
119     cout << bridge-d<<endl;
120 }
121 int main()
122 {
123     scanf("%d%d",&n,&m);
124     while(n||m)
125     {
126         init();
127         int M=m;
128         while(M--)
129         {
130             int u,v;
131             scanf("%d%d",&u,&v);
132             addedge(u,v);
133             addedge(v,u);
134         }
135         solve();
136         scanf("%d%d",&n,&m);    
137     }
138     return 0;
139 }