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

using namespace std;

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

int n, m, x, y, viz[100003], k;
vector<int> G[100003];
queue<int> q;

void dfs(int start)
{
    if (viz[start]) return;
    k++;
    q.push(start);
    while (!q.empty())
    {
        int c = q.front();
        q.pop();

        if (viz[c]) continue;
        viz[c] = 1;

        for (int i = 0; i < G[c].size(); i++)
            q.push(G[c][i]);
    }
}

int main()
{
    fin >> n >> m;
    for (int i = 0; i < m; i++)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for (int i = 1; i <= n; i++)
        dfs(i);
    fout << k;
    return 0;
}