#include <iostream>
#include <stdio.h>
#define LGMAX 100001
using namespace std;

int n,m,nc,viz[LGMAX];

struct nod{
    int inf;
    nod *urm;
};
nod *g[LGMAX];

void add(int x,int y)
{
    nod *aux=new nod;
    aux->inf=y;
    aux->urm=g[x];
    g[x]=aux;
}
void citire()
{
    freopen ("dfs.in","r",stdin);
    scanf ("%d%d",&n,&m);
    int x,y;
    for (int i=0;i<m;i++)
    {
        scanf ("%d%d",&x,&y);
        add(x,y);
        add(y,x);
    }
}
void dfs(int x)
{
    for (nod *p=g[x];p;p=p->urm)
        if (!viz[p->inf])
        {
            viz[p->inf]=1;
            dfs(p->inf);
        }
}
void numar()
{
    for (int i=1;i<=n;i++)
        if (!viz[i])
        {
            nc++;
            viz[i]=1;
            dfs(i);
        }
}

int main()
{
    citire();
    numar();
    freopen ("dfs.out","w",stdout);
    printf ("%d",nc);
    return 0;
}