#include<fstream>
#include<vector>
#define In "dfs.in"
#define Out "dfs.out"
#define N 100002
using namespace std;
int sol,n;
vector<int>v[N];
bool viz[N];

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

void Dfs(int nod)
{
    int i,lim;
    lim = v[nod].size();
    viz[nod] = 1;
    for(i=0;i<lim;i++)
        if(viz[v[nod][i]]==0)
            Dfs(v[nod][i]);
}

void Rezolvare()
{
    int i;
    for(i=1;i<=n;i++)
        if(viz[i]==0)
        {
            sol++;
            Dfs(i);
        }
}

void Afisare()
{
    ofstream fout(Out);
    fout<<sol<<"\n";
    fout.close();
}

int main()
{
    Citire();
    Rezolvare();
    Afisare();
    return 0;
}