#include <fstream>

using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,m,viz[100002];
struct nod
{
    int v;
    nod *urm;
};
nod *L[100002], *p;
int coada[100002];
void fill_coada(int x)
{
    int pr,ul,i,y,z;
    nod *p;
    coada[1]=x;
    pr=1;
    ul=1;
    viz[x]=1;
    while(pr<=ul)
    {
        y=coada[pr];
        for(p=L[y];p!=0;p=p->urm)
        {
            z=p->v;
            if(viz[z]==0)
            {
                viz[z]=1;
                ul++;
                coada[ul]=z;
            }
        }
        pr++;
    }
}
int i,x,y,c;
int main()
{
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        p=new nod;
        p->v=y;
        p->urm=L[x];
        L[x]=p;
        p=new nod;
        p->v=x;
        p->urm=L[y];
        L[y]=p;
    }
    c=0;
    for(i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            c++;
            fill_coada(i);
        }
    }
    fout<<c;
    return 0;
}