#include <fstream>

using namespace std;

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

#define N 100001

struct graf{
    int nod;
    graf *next;} *A[N];

int n, m, a, b, sol;
bool viz[N];

void add(int a, int b)
{
    graf *q = new graf;
    q -> nod = b;
    q -> next = A[a];
    A[a] = q;
}

void citire()
{
    in >> n >> m;

    for(int i=1;i<=m;i++)
        in >> a >> b, add(a,b), add(b,a);
}

void dfs(int x)
{
    viz[x] = true;
    for(graf *i = A[x]; i!=NULL; i = i->next)
        if(!viz[i->nod])
            dfs(i->nod);
}

void rezolvare()
{
    for(int i=1;i<=n;i++)
        if(!viz[i])
        {
            sol ++;
            dfs(i);
        }
}

int main()
{
    citire();
    rezolvare();

    out << sol;

    in.close();
    out.close();
    return 0;
}