#include <cstdlib>
#include <fstream>
#include <vector>
#include <stack>

using namespace std;


void dfs(int node, const vector< vector<int> > &neighbors, vector<int> &visited)
{
    stack<int>  S;
    int         x;

    S.push(node);
    while(!S.empty())
    {
        x = S.top();
        S.pop();
        if (visited[x]) continue;

        visited[x] = 1;
        for (vector<int>::const_iterator it = neighbors[x].begin(); it != neighbors[x].end(); it++)
        {
            if (!visited[*it]) S.push(*it);
        }
    }
}


int main()
{
    vector< vector<int> >   neighbors;
    vector<int>             visited;
    int                     M, N, a, b;
    int                     componentCount;
    fstream                 f, g;

    f.open("dfs.in", ios::in);
    g.open("dfs.out", ios::out);

    f >> N >> M;
    neighbors.resize(N);
    visited.resize(N, 0);
    for (int i = 0; i < M; i++)
    {
        f >> a >> b;
        a--; b--;
        neighbors[a].push_back(b);
        neighbors[b].push_back(a);
    }

    componentCount = 0;
    for (int i = 0; i< N; i++)
    {
        if (!visited[i])
        {
            componentCount++;
            dfs(i, neighbors, visited);
        }
    }

    g << componentCount;

    f.close();
    g.close();

    return 0;
}