#include <iostream>
#include <fstream>
#include <stack>
#include <iterator>
#include <vector>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");

vector <int> adjList[100001];
stack <int> a;
int n,m;
bool visited[100001];
void read()
{
    int x,y;
    f >> n >> m;
    for(int i=0;i<m;i++){
        f >> x >> y;
        adjList[x].push_back(y);
        adjList[y].push_back(x);
    }

}

void DFS(int start)
{
    int top;
    a.push(start);
    visited[start]=1;
    while(!a.empty())
    {
        top=a.top();
        a.pop();
        for(vector<int>::iterator it=adjList[top].begin();it!=adjList[top].end();it++)
        {
            int now=*it;
            if(!visited[now])
            {
                visited[now]=1;
                a.push(now);

            }
        }

    }
}

int main()
{
    read();
    int conex=0;
    for(int i=1;i<=n;i++)
    {
        if(!visited[i])
        {
            DFS(i);
            conex++;
        }
    }
    g << conex;
    return 0;
}