#include <iostream>
#include <fstream>
#include <algorithm>
#include <cctype>

#define pb push_back
#define mp make_pair
#define MAXN 100001
#define DIM 8192

using namespace std;

class Reader
{
public:
    Reader(const char* filename)
    {
        f.open(filename);
        pos = 0;
        f.read(buffer,DIM);
    }
    inline Reader& operator >>(int& x)
    {
        x=0;
        sgn=1;
        while((buffer[pos]<'0'||buffer[pos]>'9')&&buffer[pos]!='-')
            if(++pos==DIM)
                f.read(buffer,DIM),pos=0;
        if(buffer[pos]=='-')sgn=-1,pos++;
        while(buffer[pos]>='0'&&buffer[pos]<='9')
        {
            x=x*10+buffer[pos]-'0';
            if(++pos==DIM)f.read(buffer,DIM),pos=0;
        }
        x*=sgn;
        return (*this);
    }
    inline Reader& operator >>(char* c)
    {
        aux = 0;
        while(isspace(buffer[pos]))
            if(++pos==DIM)
                f.read(buffer,DIM),pos=0;
        while(!isspace(buffer[pos]))
        {
            c[aux++]=buffer[pos];
            if(++pos==DIM)f.read(buffer,DIM),pos=0;
        }
        return (*this);
    }
    ~Reader()
    {
        f.close();
    }
private:
    ifstream f;
    int pos,aux,sgn;
    char buffer[DIM];
};

class Writer
{
public:
    Writer(const char* filename)
    {
        g.open(filename);
        pos = 0;
    }
    inline Writer& operator <<(int xx)
    {
        aux = 0;
        x = xx;
        if(xx<0)x=-x;
        if(x==0)
            nr[aux++]='0';
        while(x)
        {
            nr[aux++]=x%10+'0';
            x/=10;
        }
        if(xx<0)nr[aux++]='-';
        while(aux>0)
        {
            buffer[pos++]=nr[--aux];
            if(pos==DIM)g.write(buffer,DIM),pos=0;
        }
        return (*this);
    }
    inline Writer& operator <<(const char* c)
    {
        aux = 0;
        while(c[aux])
        {
            buffer[pos++]=c[aux++];
            if(pos==DIM)g.write(buffer,DIM),pos=0;
        }
        return (*this);
    }
    ~Writer()
    {
        g.write(buffer,pos);
        g.close();
    }
private:
    ofstream g;
    int pos,aux,x;
    char buffer[DIM],nr[21];
};

Reader f("dfs.in");
Writer g("dfs.out");

int n,m,t[MAXN],h[MAXN],i,a,b,nr,A,B;

int tata(int nod)
{
    if(t[nod]==nod)return nod;
    return t[nod]=tata(t[nod]);
}

int main()
{
    f>>n>>m;
    for(i=1;i<=n;i++)t[i]=i;
    while(m--)
    {
        f>>A>>B;
        a=tata(A);
        b=tata(B);
        if(a!=b)
        {
            nr++;
            if(h[a]>h[b])t[b]=a;
            else t[a]=b;
            if(h[a]==h[b])h[a]++;
        }
    }
    g<<n-nr;
    return 0;
}