#include<bits/stdc++.h>

using namespace std;

const int N=5010,M=20010;

int h[N],e[M],ne[M],idx;
int n,m;
int dfn[N],low[N],timestamp;
int stk[N],top;
int id[N],dcc_cnt;
bool is_bridge[N];
int d[N];

void add(int a,int b)
{
    e[idx]=b;
    ne[idx]=h[a];
    h[a]=idx++;
}

void tarjan(int u,int from)
{
    dfn[u]=low[u]=++timestamp;
    stk[++top]=u;

    for(int i=h[u];~i;i=ne[i])
    {
        int j=e[i];
        if(!dfn[j])
        {
            tarjan(j,i);
            low[u]=min(low[u],low[j]);
            if(dfn[u]<low[j])
                is_bridge[i]=is_bridge[i^1]=true;
        }
        else if(i!=(from^1))
        {
            low[u]=min(low[u],dfn[j]);
        }
    }

    if(dfn[u]==low[u])
    {
        ++dcc_cnt;
        int y;
        do
        {
            y=stk[top--];
            id[y]=dcc_cnt;
        }while(y!=u);
    }
}

signed main()
{
    cin>>n>>m;
    memset(h,-1,sizeof h);
    while(m--)
    {
        int a,b;
        cin>>a>>b;
        add(a,b);
        add(b,a);
    }

    tarjan(1,-1);

    for(int i=0;i<idx;i++)
    {
        if(is_bridge[i])d[id[e[i]]]++;
    }

    int cnt=0;
    for(int i=1;i<=dcc_cnt;i++)
    {
        if(d[i]==1)
        {
            cnt++;
        }
    }
    cout<<(cnt+1)/2<<endl;

    return 0;
}