#include <fstream>

using namespace std;

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

const int NMAX=100005;
int n,m,used[NMAX],count;

typedef struct nod{
    int x;
    nod *urm;
}*pNod;
pNod v[NMAX];

void add (pNod &dest, int val)
{
    pNod p;
    p=new nod;
    p->x=val;
    p->urm=dest;
    dest=p;
}

void read ()
{
    fin>>n>>m;
    for (int i=1, nod1, nod2; i<=m; i++)
    {
        fin>>nod1>>nod2;
        add (v[nod1],nod2);
        add (v[nod2],nod1);
    }
}

void DFS (int punct)
{
    pNod p;
    used[punct]=1;
    for (p=v[punct]; p!=NULL; p=p->urm)
        if (!used[p->x])
            DFS (p->x);
}


int main ()
{
    read ();
    for (int i=1; i<=n; i++)
    {
        if (!used[i])
        {
            count++;
            DFS (i);
        }
    }
    fout<<count;

    fin.close();fout.close();
    return 0;
}