void tarjan(int x)

{

    low[x]=dfn[x]=++ind;

    q[++top]=x;mark[x]=;

    for(int i=last[x];i;i=e[i].next)

        if(!dfn[e[i].to])

        {

            tarjan(e[i].to);

            low[x]=min(low[x],low[e[i].to]);

        }

        else if(mark[e[i].to])

            low[x]=min(low[x],dfn[e[i].to]);

    if(low[x]==dfn[x])

    {

        int now=;scc++;

        while(now!=x)

        {

            now=q[top--];mark[now]=;

            bl[now]=scc;num[scc]++;

        }

    }

}

#include<iostream>

#include<cstdio>

#include<cstdlib>

#include<cmath>

#include<cstring>

#include<algorithm>

#include<stack>

#include<vector>

using namespace std;

const int maxn=;

int first[maxn],to[maxn],next[maxn],cnt,from[maxn];

void add(int u,int v)

{

    from[++cnt]=u;

    to[cnt]=v;

    next[cnt]=first[u];

    first[u]=cnt;

}

int dfn[maxn],low[maxn],vis[maxn],ind,scc,now,st[maxn],top;

int isc[maxn];

vector<int> bl[maxn];

int blc;

int tag[maxn];

void Tarjan_dfs(int x,int fa)

{

    int son=;

    low[x]=dfn[x]=++ind;

    for(int i=first[x];i;i=next[i])

    {

        int now=to[i];

        if(!dfn[now])

        {

            st[++top]=i;son++;

            Tarjan_dfs(now,x);

            low[x]=min(low[x],low[now]);

            if(low[now]>=dfn[x])

            {

                isc[x]=;

                bl[++blc].clear();

                while()

                {

                    int num=st[top--];

                    if(tag[from[num]]!=blc)

                    {

                        bl[blc].push_back(from[num]);

                        tag[from[num]]=blc;

                    }

                    if(tag[to[num]]!=blc)

                    {

                        bl[blc].push_back(to[num]);

                        tag[to[num]]=blc;

                    }

                    if(to[num]==now && from[num]==x)break;

                }

            }

        }

        else if(dfn[now]<dfn[x] && now!=fa)

        {

            st[++top]=i;

            low[x]=min(low[x],dfn[now]);

        }

    }

    if(fa== && son==)isc[x]=;

}

int main()

{

    int n,m;

    scanf("%d%d",&n,&m);

    for(int i=;i<=m;i++)

    {

        int u,v;

        scanf("%d%d",&u,&v);

        add(u,v);

        add(v,u);

    }

    for(int i=;i<=n;i++)if(!dfn[i])Tarjan_dfs(i,-);

    cout<<blc<<endl;

    return ;

}

#include<iostream>

#include<cstdio>

#include<cstdlib>

#include<cmath>

#include<cstring>

#include<algorithm>

#include<stack>

#include<vector>

using namespace std;

const int maxn=;

int first[maxn],to[maxn],next[maxn],cnt,from[maxn];

void add(int u,int v)

{

    from[++cnt]=u;

    to[cnt]=v;

    next[cnt]=first[u];

    first[u]=cnt;

}

int dfn[maxn],low[maxn],vis[maxn],ind,scc,now,st[maxn],top;

int isb[maxn];

vector<int> bl[maxn];

int blc;

int tag[maxn];

void Tarjan_dfs(int x,int fa)

{

    dfn[x]=low[x]=++ind;

    for(int i=first[x];i;i=next[i])

    {

        int v=to[i];

        if(!dfn[v])

        {

            Tarjan_dfs(v,x);

            low[x]=min(low[x],low[v]);

            if(low[v]>dfn[x])

                isb[i]=isb[i^]=;

        }

        else if(dfn[v]<dfn[x] && v!=fa)low[x]=min(low[x],dfn[v]);

    }

}

int vis[maxn];

void dfs(int x)

{

    vis[x]=;

    tag[x]=blc;

    for(int i=first[x];i;i=next[i])

    {

        int v=to[i];

        if(isb[v])continue;

        if(!vis[i])dfs(v);

    }

}

int main()

{

    int n,m;

    scanf("%d%d",&n,&m);

    for(int i=;i<=m;i++)

    {

        int u,v;

        scanf("%d%d",&u,&v);

        add(u,v);

        add(v,u);

    }

    for(int i=;i<=n;i++)if(!dfn[i])Tarjan_dfs(i,-);

    for(int i=;i<=n;i++)if(!vis[i]){blc++;dfs(i);}

    cout<<blc<<endl;

    return ;

}