#include <fstream>
#include <vector>

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


vector<vector<int>> edges;
vector<bool> viz;

void readGraph()
{
    int n;
    in >> n;
    int m;
    in >> m;
    edges.resize(n);
    viz.resize(n);
    for (int i = 0; i < m; i++)
    {
        int a, b;
        in >> a >> b;
        a--;
        b--;
        edges[a].push_back(b);
        edges[b].push_back(a);
    }
}

void dfs(int node)
{
    viz[node] = 1;
    for (int i = 0; i < edges[node].size(); i++)
    {
        int next = edges[node][i];
        if (viz[next] == 0)
        {
            dfs(next);
        }
    }
}

int main()
{
    readGraph();
    int cntr = 0;
    for (int i = 0; i < edges.size(); i++)
    {
        if (viz[i] == 0)
        {
            cntr++;
            dfs(i);
        }
    }
    out << cntr;
    return 0;
}