#include <fstream>
#include <vector>
#define NMAX 100002
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,nrc,m;
vector <int> G[NMAX];
int uz[NMAX];

void citire();
void afisare();
void dfs(int x);
int main()
{
    citire();
    for(int i=1;i<=n;i++)
    {
        if(!uz[i])
        {
            nrc++;
            dfs(i);
        }
    }
    afisare();
    return 0;
}

void citire()
{   int x,y;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        G[y].push_back(x);
        G[x].push_back(y);
    }
}

void dfs(int x)
{
     int i;
     uz[x]=nrc;     ///il marchez pe x ca vizitat
     ///parcurg toti vecinii lui x in ordine crescatoare
     for(i=0;i<G[x].size();i++)
        if(!uz[G[x][i]])
            dfs(G[x][i]);
}

void afisare()
{
    fout<<nrc<<'\n';
}