//http://www.infoarena.ro/problema/dfs - 30pct
#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>

using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

#define MAXN 100050

int n;
bitset <MAXN> viz;
vector <int> G[MAXN];

void Read()
{
    int x, y, m;
    f >> n >> m;
    for(int i = 1; i <= m; i++)
        f >> x >> y, G[x].push_back(y), G[y].push_back(x);
}

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

int main()
{
    int k = 0;
    Read();
    for(int i = 0; i < n; i++)
        if(!viz[i])
            DFS(i), k++;
    g << k;
    return 0;
}