#include<fstream>

using namespace std;

ifstream cin("dfs.in");
ofstream cout("dfs.out");

struct nod
{
    int info;
    nod * next;
};

nod * lda[100004];
int v[100004];

void add(int x, nod * &y)
{
    nod * p= new(nod);
    p->info = x;
    p->next = y;
    y=p;
}

void dfs(int k)
{
    v[k]=1;
    for (nod * p=lda[k];p;p=p->next)
         if (!v[p->info])
         dfs(p->info);
}

int main()
{
    int n, m;
    cin >> n >> m;
    while (m--)
    {
        int x,y;
        cin>>x>>y;
        add(y,lda[x]);
        add(x,lda[y]);
    }
    int cnt = 0;
    for (int i=1;i<=n;i++)
        if (!v[i]) dfs(i), cnt++;
    cout << cnt;
    return 0;
}