#include <iostream>
#include <fstream>
using namespace std;
int vf[200001], urm[200001], lst[200001], viz[200001], nr = 0;
ifstream in("dfs.in");
ofstream out("dfs.out");
void adauga(int x, int y)
{
    ++nr;
    vf[nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

void dfs(int x)
{
    viz[x] = true;
    int p = lst[x], y;
    while(p != 0)
    {
        y = vf[p];
        if(!viz[y])
        {
            dfs(y);
        }
        p = urm[p];
    }
}

int main()
{
    int n, m, x, y, i, cnt = 0;
    in >> n >> m;
    for(i = 1; i <= m; i++)
    {
        in >> x >> y;
        adauga(x, y);
        adauga(y, x);
    }
    for(i = 1; i <= n; i++)
    {
        if(!viz[i])
        {
            cnt++;
            dfs(i);
        }
    }
    out << cnt;

    return 0;
}