#include <cstdio>

using namespace std;
int n,m,viz[100005],nr;
struct nod
{
    int val;
    nod *urm;
}*l[100005];
void add(int z,nod *&p)
{
    nod *q=new nod;
    q->val=z;
    q->urm=p;
    p=q;
}
void citire()
{
    scanf("%d %d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        int x,y;
        scanf("%d %d",&x,&y);
        add(x,l[y]);
        add(y,l[x]);
    }
}
void dfs(int v)
{
    viz[v]=1;
    for(nod *i=l[v];i;i=i->urm)
    {
        if(!viz[i->val])
            dfs(i->val);
    }
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    citire();
    for(int i=1;i<=n;i++)
        if(viz[i]==0)
        {
            nr++;
            dfs(i);
        }
    printf("%d\n",nr);
    return 0;
}