#include<fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int viz[100005],nr,i,n,m;
struct nod
{
    int inf;
    nod *adr;
} *v[100005];
void creare()
{   f>>n>>m;
    int i;
    for(i=1;i<=m;i++)
    {
        nod *p;
        int x,y;
        f>>x>>y;
        p=new nod;
        p->inf=y;
        p->adr=v[x];
        v[x]=p;
        p=new nod;
        p->inf=x;
        p->adr=v[y];
        v[y]=p;
    }
}
void dfs(int x)
{
    viz[x]=1;
    for(nod *p=v[x];p!=NULL;p=p->adr)
        if(viz[p->inf]==0)
            dfs(p->inf);
}
int main()
{
    creare();
    for(i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            nr++;
            dfs(i);
        }
    }
    g<<nr;
    return 0;
}