#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

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

vector <int> G[200005];

bool vizitat[200005];
int i, n, x, m, y, insule = 0;

void DFS(int nod)
{
    for (unsigned int i = 0; i < G[nod].size(); i++)
    {
        if (vizitat[nod] == 0)
        {
            vizitat[nod] = 1;
        }
    }
}

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