#include <iostream>
#include <fstream>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

struct nod{int vf; nod *urm;}*prim[100005];
int n,m,viz[100005];

void adinc(nod *&prim, int x)
{
    nod *p=new nod;
    p->vf=x; p->urm=prim;
    prim=p;
}

void citire()
{
    int i,x,y; fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        adinc(prim[x],y);
        adinc(prim[y],x);
    }
}

void dfs(int x)
{
    viz[x]=1;
    for(nod *p=prim[x];p;p=p->urm)
        if(viz[p->vf]==0)dfs(p->vf);
}

int main()
{
    citire(); int k=0;
    for(int i=1;i<=n;i++)
        if(viz[i]==0)
        {k++;dfs(i);}
    fout<<k;
    return 0;
}