#include <fstream>
#include <vector>
#define DMAX 100000
using namespace std;
FILE * fin = fopen ("dfs.in", "r");
FILE * fout = fopen ("dfs.out", "w");

void citire();
void DFS(int);

int n, m;
bool use[DMAX];

vector <int> lista[DMAX];

int main()
{
    int i, nr=0;
    
    citire();
    
    for (i=1; i<=n; i++)
        if (!use[i])
        {
            nr++;
            DFS(i);
        }
    
    fprintf(fout, "%d\n", nr);
    
    fclose(fin);
    fclose(fout);
    return 0;
}

void citire()
{
    int i, a, b;
    
    fscanf(fin, "%d %d", &n, &m);
    for (i=1; i<=m; i++)
    {
        fscanf(fin, "%d %d", &a, &b);
        lista[a].push_back(b);
        lista[b].push_back(a);
    }
    
}

void DFS(int vf)
{
    int i, nr;
    
    use[vf]=1;
    nr=(int)lista[vf].size();
    for (i=0; i<nr; i++)
        if (!use[lista[vf][i]])
            DFS(lista[vf][i]);
}