#include <fstream>
#include <vector>

using namespace std;

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

int const NLIM = 100005;
int n, m, s, ins = 0;
bool  apar[NLIM];
vector < int > muchii[NLIM];

void DFS(int nod)
{
    apar[nod] = true;
    for(unsigned int i = 0; i < muchii[nod].size(); i++)
    {
        int vecin = muchii[nod][i];
        if(apar[vecin] != 1)
        {
            DFS(vecin);
        }
    }
}

void citire()
{
    fin >> n >> m;
    for(int i = 1; i<=m; i++)
    {
        int x, y;
        fin >> x >> y;
        muchii[x].push_back(y);
        muchii[y].push_back(x);
    }

    for(int i = 1; i<=n; i++)
    {
        if(apar[i]!=1)
        {
             DFS(i);
             ++ins;
        }
    }
fout << ins;
}

int main()
{
    citire();
}