#include <fstream>

using namespace std;

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

long int n,m,h=1; bool s[100001];

struct noda
{
    int inf;
    noda*adr;
}*v[100001];

void citire()
{
    long int x,y,l; noda* p;
    fin>>n>>m;
    for(long int i=1;i<=m;i++)
    {
        fin>>x>>y;
        for(long int j=1;j<=2;j++)
        {
            if(!v[x])
            {
                v[x]=new noda;
                p=new noda;
                p->inf=y;
                p->adr=0;
                v[x]->inf=x;
                v[x]->adr=p;
            }
            else
            {
                noda*d=v[x];
                while(d->adr) d=d->adr;
                p=new noda;
                p->inf=y;
                p->adr=0;
                d->adr=p;
            }
            l=x; x=y; y=l;
        }
    }
}

void dfs(long int nod)
{
    s[nod]=1;
    noda* p=v[nod];
    for(p=v[nod];p!=NULL;p=p->adr) if(!s[p->inf]) dfs(p->inf);
}

int muchii()
{
   for(long int i=1;i<=n;i++) if(!s[i]) {dfs(i); h++;}
   return h;
}

int main()
{
    citire();
    dfs(1);
    fout<<muchii();
}