#include <iostream>
#include <fstream>
#define VMAX 100000
using namespace std;

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

int deg[VMAX], *adj[VMAX];
bool viz[VMAX];
int n, m, x, y;

struct Edge
{
    int x, y;
};

Edge edges[VMAX];

void DFS(int u)
{
    viz[u] = true;
    for (int i = 0; i < deg[u]; i++)
        if (viz[adj[u][i]] == false) DFS(adj[u][i]);
}

int main()
{
    fin >> n >> m;

    for (int i = 0; i < m; i++)
    {
        fin >> x >> y;
        x--, y--;
        deg[x]++, deg[y]++;
        edges[i].x = x, edges[i].y = y;
    }

    for (int i = 0; i < n; i++)
        adj[i] = new int[deg[i]], deg[i] = 0;

    for (int i = 0; i < m; i++)
    {
        x = edges[i].x, y = edges[i].y;
        adj[x][deg[x]++] = y;
        adj[y][deg[y]++] = x;
    }

    int nr_conexe = 0;

    for (int i = 0; i < n; i++)
        if (viz[i] == false)
        DFS(i), nr_conexe++;

    fout << nr_conexe;

    fin.close();
    fout.close();
    return 0;
}