#include <cstdio>#include <algorithm>#include <cstring>#include <vector>using namespace std;const int N=5010,M=10010;int e[M][2],cut[M],g[N],v[M<<1],nxt[M<<1],ed=1;int f[N],dfn[N],low[N],num,cnt,from[N],d[N];void add(int x,int y){v[++ed]=y;nxt[ed]=g[x];g[x]=ed;}void tarjan(int x){    dfn[x]=low[x]=++num;    for(int i=g[x];i;i=nxt[i])if(!dfn[v[i]]){        f[v[i]]=i>>1,tarjan(v[i]);        if(low[x]>low[v[i]])low[x]=low[v[i]];    }else if(f[x]!=(i>>1)&&low[x]>dfn[v[i]])low[x]=dfn[v[i]];    if(f[x]&&low[x]==dfn[x])cut[f[x]]=1;}void dfs(int x,int y){    from[x]=y;    for(int i=g[x];i;i=nxt[i])if(!from[v[i]]&&!cut[i>>1])dfs(v[i],y);}int n,m; int main(){    while(~scanf("%d%d",&n,&m)){        memset(g,0,sizeof(g));        memset(d,0,sizeof(d));        memset(from,0,sizeof(from));        memset(f,0,sizeof(f));        memset(cut,0,sizeof(cut));        num=0; ed=1; // g初始化为0的时候，ed一定要为1        for(int i=1;i<=m;i++){            int u,v;            scanf("%d%d",&u,&v);            e[i][0]=u; e[i][1]=v;            add(u,v);add(v,u);        }tarjan(1); cnt=0;        for(int i=1;i<=n;i++)if(!from[i])dfs(i,++cnt);        for(int i=1;i<=m;i++){            if(from[e[i][0]]!=from[e[i][1]]){                d[from[e[i][0]]]++;                d[from[e[i][1]]]++;            }        }int res=0;		    //for(int i=1;i<=n;i++)printf("%d %d\n",from[i],d[i]);        for(int i=1;i<=n;i++)if(d[i]==1)res++;        printf("%d\n",(res+1)/2);    }return 0;}