#include<map>

#include<set>

#include<list>

#include<cmath>

#include<queue>

#include<stack>

#include<vector>

#include<cstdio>

#include<cstring>

#include<iostream>

#include<algorithm>

#define fi first

#define se second

#define mp make_pair

#define pb push_back

#define pii pair<int,int>

#define C 0.5772156649

#define pi acos(-1.0)

#define ll long long

#define mod 1000000007

#define ls l,m,rt<<1

#define rs m+1,r,rt<<1|1

using namespace std;

using namespace __gnu_cxx;

const double g=10.0,eps=1e-;

const int N=+,maxn=+,inf=0x3f3f3f;

vector<int>v[N];

int dfn[N],low[N];

int index,num;

map<int,int>ma[N];

void tarjan(int u,int f)

{

    low[u]=dfn[u]=++index;

    for(int i=;i<v[u].size();i++)

    {

        int x=v[u][i];

        if(x==f)continue;

        if(!dfn[x])

        {

            tarjan(x,u);

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

            if(low[x]>dfn[u])ma[x][u]=ma[u][x]=;

        }

        else low[u]=min(low[u],dfn[x]);

    }

}

void dfs(int u,int f)

{

    dfn[u]=num;

    for(int i=;i<v[u].size();i++)

    {

        int x=v[u][i];

        if(x!=u&&!dfn[x]&&!ma[x][u])dfs(x,u);

    }

}

int main()

{

    int n,m;

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

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

    {

        int a,b;

        scanf("%d%d",&a,&b);

        v[a].pb(b);

        v[b].pb(a);

    }

    index=num=;

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

        if(!dfn[i])

            tarjan(i,-);

    memset(dfn,,sizeof dfn);

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

        if(!dfn[i])

        {

            ++num;

            dfs(i,-);

        }

    memset(low,,sizeof low);

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

    {

        for(int j=;j<v[i].size();j++)

        {

            if(dfn[i]!=dfn[v[i][j]])

            {

                low[dfn[i]]++;

                low[dfn[v[i][j]]]++;

            }

        }

    }

    int ans=;

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

    {

       // cout<<low[i]<<endl;

        if(low[i]==)

            ans++;

    }

    printf("%d\n",(ans+)/);

    return ;

}

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