#include <iostream>
#include <vector>
#include <fstream>
#include <cstring>
#include <queue>

using namespace std;

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

bool visited[100002] = {};
vector<int> adj[100002];
queue<int> q;

void DFS(int node)
{
    q.push(node);
    visited[node] = true;
    while(!q.empty()){
        int next_node = q.front();
        q.pop();
        for(int i = 0; i < adj[next_node].size(); i++){
            if(visited[adj[next_node][i]] == false){
                q.push(adj[next_node][i]);
                visited[adj[next_node][i]] = true;
            }
        }
    }
}

int main()
{
    int N, M, nr = 0;;
    input >> N >> M;
    for(int i = 0; i < M; i++){
        int x, y;
        input >> x >> y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    for(int i = 1; i <= N; i++){
        if(visited[i] == true){
            continue;
        }
        DFS(i);
        nr++;
    }

    output << nr;
    return 0;
}