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

const int Nmax=100000;

int nr=0;
bool viz[Nmax+1];
int st[Nmax], vf;
vector<int> v[Nmax+1];
vector<int>::iterator it;

void DFS(int) ;

int main()
{
    int i, n, m, x, y;
    fscanf(fin, "%d %d", &n, &m);
    for(i=0; i<m; ++i)
    {
        fscanf(fin, "%d %d", &x, &y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1; i<=n; ++i)
        if(!viz[i]) DFS(i);
    fout<<nr<<'\n';
    return 0;
}


void DFS(int nod)
{
    nr++; viz[nod]=1;
    st[0]=nod; vf=0;
    while(vf>=0)
    {
        nod=st[vf]; vf--;
        for(it=v[nod].begin(); it!=v[nod].end(); ++it)
            if(!viz[*it])
            {
                vf++;
                st[vf]=*it;
                viz[*it]=1;
            }
    }
}