#include<map>
#include<set>
#include<cmath>
#include<stack>
#include<queue>
#include<cstdio>
#include<string>
#include<vector>
#include<cstring>
#include<iomanip>
#include<sstream>
#include<iostream>
#include<algorithm>
#define INF 0x3f3f3f3f
#define ls l,m,rt<<1
#define rs m+1,r,rt<<1|1
//#define ll __int64
//#define int ll
typedef  long long ll;
typedef unsigned long long ull;
const int MAXN=2e5+10;
const int MOD=1e9+7;
const double eps=1e-6;
const double finf=1e10;
using namespace std;
template<class T>inline void read(T &res)
{
    char c;T flag=1;
    while((c=getchar())<'0'||c>'9')if(c=='-')flag=-1;res=c-'0';
    while((c=getchar())>='0'&&c<='9')res=res*10+c-'0';res*=flag;
}
//-------------------------------------------//
int n,m,dfcnt,num,dfn[MAXN],low[MAXN],con[MAXN],head[MAXN],ins[MAXN];
stack<int> s;
struct eddges
{
    int to,next;
}e[MAXN];
void tarjan(int u,int f)
{
    dfn[u]=low[u]=++dfcnt;
    s.push(u);
    ins[u]=1;
    bool flag=0;
    for(int i=head[u];~i;i=e[i].next)
    {
        int v=e[i].to;
        if(v==f&&!flag){flag=1;continue;}
        if(!dfn[v])
        {
            tarjan(v,u);
            low[u]=min(low[u],low[v]);
        }
        else if(ins[v])low[u]=min(low[u],dfn[v]);
    }
    if(dfn[u]==low[u])
    {
        num++;
        int t;
        do
        {
            t=s.top();
            s.pop();
            con[t]=num;
            ins[t]=0;
        }while(t!=u);
    }
}
int counter;
void add(int u,int v)
{
    e[counter].to=v;
    e[counter].next=head[u];
    head[u]=counter++;
}
int deg[MAXN],mu[MAXN],mv[MAXN];
int main()
{
    //freopen("input.txt","r",stdin);
        scanf("%d%d",&n,&m);
        memset(head,-1,sizeof head);
        for(int i=0;i<m;++i)
        {
            int u,v;
            read(u);read(v);
            add(u,v);
            add(v,u);
            mu[i]=u;
            mv[i]=v;
        }
        for(int i=1;i<=n;++i)
            if(!dfn[i])tarjan(i,-1);
        int ans=0;
        for(int i=0;i<m;++i)
        {
            if(con[mu[i]]!=con[mv[i]])
            {
                deg[mu[i]]++;
                deg[mv[i]]++;
            }
        }
        for(int i=1;i<=n;++i){
            if(deg[i]==1)ans++;}
        printf("%d\n",(ans+1)/2);
    return 0;
}