#include <stdio.h>

int n, m, viz[100005], cnt;

 struct nod
{
    int x;
    nod *urm;
} ;
nod *p[100005];

void adaug(int z,nod *&p)
{
    nod *t;
    t = new nod;
    t -> x = z;
    t -> urm = p;
    p=t;
}

void citire()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    scanf("%d %d",&n,&m);
    int i, x, y;

    for (i = 1; i <= m; i++)
    {
        scanf("%d %d",&x,&y);
        adaug(y,p[x]);
        adaug(x,p[y]);
    }
}

void DFS(int x)
{
    nod *q;
    viz[x] = 1;
    for (q = p[x]; q != NULL; q = q -> urm)
        if (!viz[q -> x]) DFS(q -> x);
}

int main()
{
    citire();
    int i;
    for (i = 1; i <= n; i++) if (!viz[i]) { cnt++; DFS(i);}
    printf("%d\n",cnt);
    return 0;
}