#include <stdio.h>
using namespace std;
int n, m, viz[100005], cnt;

typedef struct nod{int x; nod *a;} *pNod;
pNod v[100005];

void add(pNod &dest, int val)
{
    pNod p;
    p= new nod;
    p->x=val;
    p->a=dest;
    dest=p;
}

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);
        add(v[x], y);
        add(v[y], x);
    }
}

void DFS(int nod)
{
    pNod p;
    viz[nod] = 1;
    for(p=v[nod]; p!=NULL; p=p->a)
        if(!viz[p->x])
            DFS(p -> x);
}

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