#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

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

vector <int>l[100005];
bool v[100005];

void dfs(int nod)
{
    v[nod]=1;
    for (int i=0;i<l[nod].size();i++)
    {
        int vec=l[nod][i];
        if (v[vec]==0) dfs(vec);
    }
}

int i,n,m,x,y,nr;

int main()
{
    fin >> n >> m;
    for (i=1;i<=m;i++)
    {
        fin >> x >> y;
        l[x].push_back(y);
        l[y].push_back(x);
    }
    for (i=1;i<=n;i++) sort(l[i].begin(),l[i].end());
    for (i=1;i<=n;i++) if (v[i]==0)
    {
        nr++;
        dfs(i);
    }
    fout << nr;

    return 0;
}