#include<stdio.h>
#define Nmx 100001


int n,m,viz[Nmx],qu[Nmx];

struct nod
{
    int inf;
    nod *urm;
};

nod *G[Nmx];

void insert(int x,int y)
{
    nod *aux;
    aux=new nod;
    aux->urm=G[x];
    aux->inf=y;
    G[x]=aux;
}

void citire()
{
    scanf("%d%d",&n,&m);
    int x,y;
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        insert(x,y);
        insert(y,x);
    }
}

void dfs()
{
    int nr=0;
    for(int i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            nr++;
            int st,dr;
            st=dr=1;
            qu[1]=i;
            viz[i]=1;
            while(st<=dr)
            {
                for(nod *p=G[qu[st]];p!=NULL;p=p->urm)
                {
                    if(!viz[p->inf])
                    {
                        viz[p->inf]=1;
                        qu[++dr]=p->inf;
                    }
                }
                ++st;
            }
        }
    }
    printf("%d\n",nr);
}

int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);

    citire();
    dfs();

    return 0;
}