#include <fstream>

using namespace std;

int n,i,m,y,a[100005],x,c;

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

typedef struct nod
{
    int x;
    nod *a;
} *pNod;
pNod v[100005];

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

void citire()
{

    fin>>n>>m;


    for (i = 1; i <= m; i++)
    {
        fin>>x>>y;
        add(v[x], y);
        add(v[y], x);
    }
}

void df(int nod)
{
    pNod p;a[nod] = 1;
    for (p = v[nod]; p != NULL; p = p -> a)
        if (!a[p -> x])
         df(p -> x);
}

int main()
{
    citire();
    for (i = 1; i <= n; i++)
        if(!a[i])
        {c++;df(i);}
    fout<<c;
    return 0;
}