#include <fstream>
#include <vector>
#include <stack>
#define MAX 100004

using namespace std;

vector<int> v[MAX];
vector<int> q;
int n, m;
int vis[MAX];

void read();
void dfs();
bool checkStack(int x);

int main()
{
    read();
    dfs();
    return 0;
}

void read(){
    ifstream fin ("dfs.in");
    fin >> n >> m;
    int x, y;
    for (int i = 1; i <= m; ++i){
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    fin.close();
}

void dfs(){
    int k(0);
    for (int i = 1; i <= n; ++i){
        if (vis[i])
            continue;
        ++k;
        q.push_back(i);
        while(!q.empty()){

            int u = q.back();
            q.pop_back();

            if (!vis[u])
            {
                vis[u] = 1;
                for (unsigned int i = 0; i < v[u].size(); ++i)
                    if (!vis[v[u][i]])
                        q.push_back(v[u][i]);
            }
        }
    }

    ofstream fout ("dfs.out");
    fout << k;
    fout.close();
}