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

using namespace std;

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

int n, m;
vector<int> v[200001];
int viz[200001];

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

int main() {
    f >> n >> m;
    int x, y;
    int nr = 0;

    for (int i = 1; i <= m; i++)
    {
        f >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i = 1; i <= n; i++)
        if(viz[i] != 1)
        {
            nr++;
            dfs(i);
        }

    g << nr;
}