#include <iostream>
#include <fstream>

using namespace std;

#define MAX 100001

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

typedef struct nod
{
    int vf;
    nod *urm;
} *PNOD;

int N, M, viz[MAX], nr;
PNOD vec[MAX];

void adauga (PNOD &a, int b)
{
  PNOD p = new nod;
  p->vf = b;
  p->urm = a;
  a = p;
}

void citire ()
{
    int x, y;
    in>>N>>M;
    for(int i = 1; i <= M; i++)
    {
        in>>x>>y;
        adauga (vec[x], y);
        adauga (vec[y], x);
    }
}

void DFS (int x)
{
    viz[x] = 1;
    for(PNOD p = vec[x]; p; p = p->urm)
    {
        if(!viz[p->vf])
            DFS (p->vf);
    }
}

int compConexe()
{
       for(int i = 1; i <= N; i++)
    {
        if(!viz[i])
        {
            nr++;
            DFS (i);
        }
    }

    return nr;
}


int main()
{

    citire ();
    out<<compConexe();

    return 0;
}