#include <iostream>
#include <fstream>
#include <vector>
#include <map>
#include <queue>
using namespace std;

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

const int MAX_SIZE = 2 * 100005;
vector<int> graph[MAX_SIZE];
int goneThrough[MAX_SIZE];
int relatedComponents = 0;

void markComponent(int currentPeak) {
    goneThrough[currentPeak] = 1;
    for (int i = 0; i < graph[currentPeak].size(); ++i) {
        if (goneThrough[graph[currentPeak][i]] == 0) {
            markComponent(graph[currentPeak][i]);
        }
    }
}

void findConnectedComponents(int currentPeak) {
    queue<int> peaks;
    if (goneThrough[currentPeak] == 0) {
        ++relatedComponents;
        markComponent(currentPeak);
    }
}

int main() {
    int peaks, arches;
    fin >> peaks >> arches;
    for (int i = 1; i <= arches; ++i) {
        int start, end;
        fin >> start >> end;
        graph[start].push_back(end);
        graph[end].push_back(start);
    }
    for (int peak = 1; peak <= peaks; ++peak) {
        findConnectedComponents(peak);
    }
    fout << relatedComponents;
    return 0;
}