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

vector<int> lista[100010];
bool viz[100010];
void addVertex(int x,int y)
{
    lista[x].push_back(y);
    lista[y].push_back(x);
}
void dfs(int start)
{
    stack<int> stac;
    stac.push(start);
    viz[start]=true;
    while(stac.size())
    {
        int current = stac.top();
        for(int i = 0;i<lista[current].size();i++)
        {
            if(viz[lista[current][i]]==false)
            {
                viz[lista[current][i]]=true;
                stac.push(lista[current][i]);
            }
        }
        stac.pop();
    }
}
int main()
{
    int n,m,x,y,counter=0;
    fin>>n>>m;
    for(int i = 1;i<=m;i++) fin>>x>>y,addVertex(x,y);
    for(int i =1;i<=n;i++)
    {
        if(viz[i]==false)
        {
            counter++;
            dfs(i);
        }
    }
    fout<<counter<<'\n';
    return 0;
}