#include <fstream>
#include <vector>

#define MAXN 100002

using namespace std;

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

int n, m;

vector <int> G[MAXN];

int viz[MAXN];

inline void read()
{
    int x, y;

    fin >> n >> m;

    for (int i = 1; i <= m; i++)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

inline void df(int vf)
{
    if (viz[vf] == 0)
    {
        viz[vf] = 1;

        for (vector <int> :: iterator i = G[vf].begin(); i != G[vf].end(); i++)
        {
            if (viz[*i] == 0)
                df(*i);
        }
    }
}

void solve()
{
    int contor = 0;
    for (int i = 1; i <= n; i++)
    {
        if (viz[i] == 0)
            df(i),
            contor++;
    }

    fout << contor;
}

int main ()
{
    read();
    solve();

    fin.close(); fout.close(); return 0;
}