#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

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

const int NMAX = 100000 + 5;

vector <int> graph[NMAX];
int b[NMAX];
int cnt, n, m;

void Read()
{
    fin >> n >> m;
    for (int i = 1; i <= m; ++i)
    {
        int a, b;
        fin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
}

void dfs(int node)
{
    b[node] = cnt;
    for (int i = 0; i < graph[node].size(); ++i)
        dfs(graph[node][i]);
}

int main()
{
    Read();
    for (int i = 1; i <= n; ++i)
        if (b[i] == 0)
        {
            ++cnt;
            dfs(i);
        }
    fout << cnt;
    return 0;
}