#include <fstream>
#include <vector>

using namespace std;

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

const int NMAX = 100005;

int n, m;
vector < vector < int > > G(NMAX);
bool seen[NMAX];
int ans;

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

void dfs(int node)
{
    seen[node] = true;
    for (vector < int > :: iterator it = G[node].begin(); it != G[node].end(); ++ it)
        if (!seen[*it])
        dfs(*it);
}

void solve()
{
    for (int i = 1; i <= n; ++ i)
        if (!seen[i])
            {
             ++ ans;
             dfs(i);
            }
}

int main()
{
    read();
    fin.close();
    solve();
    fout << ans << "\n";
    fout.close();
    return 0;
}