#include <iostream>
#include <fstream>
using namespace std;

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

struct nod 
{
    int info;
    nod* urm;
} *G[100005];

bool sel[100005];

void Dfs(int x)
{
    sel[x] = true;
    for (nod* p = G[x]; p; p = p->urm)
    {
        if (!sel[p->info])
            Dfs(p->info);
    }
}


int main()
{
    int n, m;
    fin >> n >> m;
    int a, b;
    for (int i = 1; i <= m; i++)
    {
        fin >> a >> b;
        nod* p = new nod;
        p->info = b;
        p->urm = G[a];
        G[a] = p;

        p = new nod;
        p->info = a;
        p->urm = G[b];
        G[b] = p;
    }

    int result = 0;
    for (int i = 1; i <= n; i++)
    {
        if (!sel[i])
        {
            result++;
            Dfs(i);
        }
    }

    fout << result;

    
    return 0;
}