#include <iostream>
#include <fstream>

using namespace std;

int n, m, viz[100005], cnt;

ifstream f("dfs.in");
ofstream g("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()
{

    f>>n>>m;
    int i, x, y;

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

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

int main()
{
    citire();
    int i;
    for (i = 1; i <= n; i++)
        if (!viz[i])
        { cnt++;
        DFS(i);}
    cout<<cnt;
}