#include <fstream>
#include <vector>
#include <bitset>
using namespace std;
ifstream cin("dfs.in");
ofstream cout("dfs.out");

#define nmax 100010

int n,m,x,y,cc;
vector<int> a[nmax];
bitset<nmax> v;

void dfs(int nod)
{
    vector<int>::iterator it;
    v.set(nod);
    for (it=a[nod].begin();it!=a[nod].end();it++)
        if (v.test(*it)==false)
            dfs(*it);
}

int main()
{
    int i,j;
    cin>>n>>m;
    for (i=1;i<=m;i++)
    {
        cin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for (i=1;i<=n;i++)
        if (v.test(i)==false)
        {
            dfs(i);
            cc++;
        }
    cout<<cc;
}