#include <bits/stdc++.h>

using namespace std;

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


#define nmax 100001

vector <int>v[nmax];
bool viz[nmax];
int n,m,nrcomponente;

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

int main()
{
    f>>n>>m;
    for(int i=1; i<=n; i++)
    {
        int x,y;
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i=1; i<=n; i++)
        if(!viz[i])
        {
            dfs(i);
            nrcomponente++;
        }
    g<<nrcomponente;
    f.close();g.close();
    return 0;
}