#include <iostream>

#include <cstdio>

#include <cstdlib>

#include <cmath>

#include <algorithm>

#include <cstring>

#include <stack>

#include <cctype>

#include <queue>

#include <string>

#include <vector>

#include <set>

#include <map>

#include <climits>

#define lson root<<1,l,mid

#define rson root<<1|1,mid+1,r

#define fi first

#define se second

#define ping(x,y) ((x-y)*(x-y))

#define mst(x,y) memset(x,y,sizeof(x))

#define mcp(x,y) memcpy(x,y,sizeof(y))

#define Min(x,y) (x<y?x:y)

#define Max(x,y) (x>y?x:y)

using namespace std;

#define gamma 0.5772156649015328606065120

#define MOD 1000000007

#define inf 0x3f3f3f3f

#define N 11005

#define maxn 5005

typedef long long LL;

typedef pair<int,int> PII;

stack<int>sk;

int n,m,hcnt,deep,block,leaf;

int d[maxn],dfn[maxn],low[maxn],head[maxn];

int color[maxn],vis[maxn];

struct Node{

    int to,next;

    Node(){}

    Node(int a,int b):to(a),next(b){}

}node[N<<];

inline void add(int x,int y){

    node[hcnt]=Node(y,head[x]);

    head[x]=hcnt++;

}

inline void init(){

    while(!sk.empty())sk.pop();

    mst(vis,);

    mst(head,-);

    mst(d,);

    mst(dfn,);

    hcnt=deep=;

    block=leaf=;

}

void dfs(int x,int fa){

    int flag=;  ///这个不是必要的,有重边时有效

    sk.push(x);

    vis[x]=;

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

    for(int i=head[x];~i;i=node[i].next){

        int e=node[i].to;

        if(e==fa&&flag){flag=;continue;}

        if(vis[e])low[x]=min(low[x],dfn[e]);

        else if(!dfn[e]){

            dfs(e,x);

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

        }

    }

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

        ++block;    ///缩点

        int co;

        do{

            co=sk.top();sk.pop();

            vis[co]=;

            color[co]=block;

        }while(co!=x);

    }

}

int main(){

    int i,j,group,Case=,x,y;

    while(scanf("%d%d",&n,&m)!=EOF){

        init();

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

            scanf("%d%d",&x,&y);

            add(x,y);

            add(y,x);

        }

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

            if(!dfn[i])dfs(i,-);

        }

        if(block==){printf("0\n");continue;}

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

        for(j=head[i];~j;j=node[j].next){

            int e=node[j].to;

            if(color[i]!=color[e])

                ++d[color[i]];   ///d数组保留的是缩点后每个点的度数

        }

        for(i=;i<=block;++i){

            if(d[i]==)leaf+=;  ///如果有孤立的点,叶子节点加2

            else if(d[i]==)++leaf;

        }

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

    }

    return ;

}