#include <iostream>
#include <vector>
#include <ifstream>

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

vector<int>graph[100001];int ct;
int x,y;
int edges;
int nodes;
bool visited[100001];

void dfs(int node){
    visited[node]=1;
    for(auto neighbour: G[node])
        if(!visited[neighbour])
            dfs(neighbour);
    
 
}

    


using namespace std;

int main()
{
    
    
     fin>>nodes;
     fin>>edges;
    
    for(i=1;i<=edges;i++)
    {
        
        fin>>x>>y;
        graph[x].push_back(y);
        graph[y].push_back(x);
        
        
    }
    for(int i=1;i<=nodes;i++)
    {   if(!visited(i))
        {   ct++;
            dfs(i);
        }
    }
    fout<<ct;
 
    
    return 0;
}