#include <cstdio>
using namespace std;

FILE *f=fopen("dfs.in","r");
FILE *g=fopen("dfs.out","w");

struct nod{
    int v;
    nod *next;
};
typedef nod *lista;

int n,m,used[100001];
lista lv[100001];

void readGRAPH()
{
    int i,a,b;
    lista p;
    fscanf(f,"%d%d",&n,&m);
    for(i=1;i<=m;++i)
    {
        fscanf(f,"%d%d",&a,&b);
        p=new nod;p->v=a;p->next=lv[b];lv[b]=p;
        p=new nod;p->v=b;p->next=lv[a];lv[a]=p;
    }
}

void DFS(int k)
{
    used[k]=1;
    for(lista p=lv[k];p;p=p->next)
            if(!used[p->v])
                    DFS(p->v);
}

int main()
{
    readGRAPH();
    int conex=0;
    for(int i=1;i<=n;++i)
        if(!used[i])
        {
            ++conex;
            DFS(i);
        }
    fprintf(g,"%d",conex);
    return 0;
}