/*==========================================================================

# Last modified: 2016-03-13 17:55

# Filename: poj3177.cpp

# Description:

==========================================================================*/

#define me AcrossTheSky

#include <cstdio>

#include <cmath>

#include <ctime>

#include <string>

#include <cstring>

#include <cstdlib>

#include <iostream>

#include <algorithm> 

#include <set>

#include <map>

#include <stack>

#include <queue>

#include <vector> 

#define lowbit(x) (x)&(-x)

#define FOR(i,a,b) for((i)=(a);(i)<=(b);(i)++)

#define FORP(i,a,b) for(int i=(a);i<=(b);i++)

#define FORM(i,a,b) for(int i=(a);i>=(b);i--)

#define ls(a,b) (((a)+(b)) << 1)

#define rs(a,b) (((a)+(b)) >> 1)

#define getlc(a) ch[(a)][0]

#define getrc(a) ch[(a)][1] 

#define maxn 100000

#define maxm 100000

#define pi 3.1415926535898

#define _e 2.718281828459

#define INF 1070000000

using namespace std;

typedef long long ll;

typedef unsigned long long ull; 

template<class T> inline

void read(T& num) {

    bool start=false,neg=false;

    char c;

    num=0;

    while((c=getchar())!=EOF) {

        if(c=='-') start=neg=true;

        else if(c>='0' && c<='9') {

            start=true;

            num=num*10+c-'0';

        } else if(start) break;

    }

    if(neg) num=-num;

}

/*==================split line==================*/

int to[maxm],next[maxm],first[maxn];

int low[maxn],dfn[maxn],s[maxn],belong[maxn],in[maxn];

bool instack[maxn];

int sume=1,scc,clo=0,top,sum=0,n,m;

void addedge(int x,int y){

	sume++; to[sume]=y; next[sume]=first[x]; first[x]=sume;

}

void tarjan(int u,int fa){

	low[u]=dfn[u]=(++clo);

	instack[u]=1;

	s[++top]=u;

	for (int i=first[u];i;i=next[i]){

		if (i==(fa^1)) continue;

		int v=to[i];

		if (!dfn[v]){

			tarjan(v,i);

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

		}

		else if (instack[v]) low[u]=min(low[u],dfn[v]);

	}

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

		scc++;

		while (true){

			int v=s[top--];

			instack[v]=false;

			belong[v]=scc;

			if (v==u) break;

		}

	}

}

int main(){

	read(n); read(m);

	FORP(i,1,m){

		int x,y;

		read(x); read(y);

		addedge(x,y); addedge(y,x);

	}

	FORP(i,1,n)

		if (!dfn[i]) tarjan(1,0);

	FORP(i,1,n)

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

			if (belong[i]!=belong[to[j]]) in[belong[i]]++;

	int sum=0;

	FORP(i,1,n) if (in[i]==1) sum++;

	printf("%d\n",(sum+1)/2);

}