#include <iostream>
#include <vector>
#include <map>
#include <cstring>
#include <fstream>
#include <sstream>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
#include <unordered_map>
#include <stack>
#include <iomanip>

using namespace std;

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

const int N = 1005;
int n, m;
int mat[N][N];
set<int> visited;

void dfs(int node) {
    visited.insert(node);
    for (int i = 1; i <= n; ++i) {
        if (mat[node][i] && !visited.count(i)) {
            dfs(i);
        }
    }
}

int main() {
    fin >> n >> m;

    for (int i = 0; i < m; ++i) {
        int x, y;
        fin >> x >> y;

        mat[x][y] = mat[y][x] = 1;
    }

    int ans = 0;
    for (int i = 1; i <= n; ++i) {
        if (!visited.count(i)) {
            ++ans;
            dfs(i);
        }
    }

    fout << ans;

    return 0;
}