#include <fstream>
#include <vector>

using namespace std;
vector<int> g[100000];
bool viz[100000];

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

int dfs(int nod) {
    if(viz[nod]) return 0;
    int res = 1;
    viz[nod] = true;
    for(auto b : g[nod]) {
        dfs(b);
    }
    return 1;
}

int main() {
    int n, m;
    in >> n >> m;
    for(int i = 0; i < m; i++) {
        int x, y;
        in >> x >> y;
        g[x-1].push_back(y-1);
        g[y-1].push_back(x-1);
    }
    in.close();
    int j = 0;
    for(int i = 0; i < n; i++) {
        if(viz[i]) continue;
        j += dfs(i);
    }
    out << j;
    return 0;
}