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

using namespace std;

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

const int  MAXN=100005;
vector<int>adj[MAXN];
bool visited[MAXN];

void dfs(int u){
    visited[u]=true;
    for(int v:adj[u]){
        if(!visited[v]) dfs(v);
    }
}

int main()
{
    int n,m,db=0;
    f>>n>>m;
    for(int i=0;i<n;i++){
        int u,v;
        f>>u>>v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for(int i=1;i<=n;i++){
        if(!visited[i]){
            db++;
            dfs(i);
        }
    }
    g<<db;
    return 0;
}