#include <fstream>
#include <vector>
#include <stack>
using namespace std;

void dfs(int start, vector<bool> &seen, const vector<vector<int>> &adj)
{
    stack<pair<int,int>> st;
    st.push({start,0});
    seen[start] = true;

    while (!st.empty()) {
        pair<int,int> &t = st.top();
        int nod = it.first;
        int i = t.second;

        if (i < adj[nod].size()) {
            int v = adj[nod][i];
            t.second = i + 1;

            if (!seen[v]) {
                seen[v] = true;
                st.push({v,0});
            }
        }
        else {
            st.pop();
        }
    }
}

int main(){
    std::ifstream fin("dfs.in");
    std::ofstream fout("dfs.out");

    int n, m;
    fin >> n >> m;

    vector<vector<int>> adj(n+1);

    for (int i = 0; i < m; ++i) {
        int a, b;
        fin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }


    vector<bool> seen(n+1, false);
    int nrComp = 0;

    for (int i = 1; i <= n; ++i) {
        if (!seen[i]) {
            ++nrComp;
            dfs(i, seen, adj);
        }
    }

    fout << nrComp << endl;
}