#include <fstream>

using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

struct node
{
    int x;
    node * next;
};

void dfs(int);
void citire();
void conex();
void insertNode(node * &, int);

int n, m;
bool uz[100005];
node * G[100005];

int main()
{
    citire();
    conex();
    return 0;
}

void dfs(int x)
{
    uz[x] = true;
    for (node * p = G[x]; p; p = p->next)
        if (!uz[p->x])
            dfs(p->x);
}

void conex()
{
    int comp = 0;
    for (int i = 1; i <= n; i++)
        if (!uz[i])
        {
            dfs(i);
            comp++;
        }
    fout << comp << '\n';
}

void insertNode(node * & list, int x)
{
    node * p = new node;
    p->x = x;
    p->next = list;
    list = p;
}

void citire()
{
    fin >> n >> m;

    int x, y;
    for (int i = 1; i <= m; i++)
    {
        fin >> x >> y;
        insertNode(G[x], y);
        insertNode(G[y], x);
    }
}