#include <bits/stdc++.h>

using namespace std;
ifstream in("dfs.in");
ofstream out("dfs.out");
const int nx=100002;
vector < int > v[nx];
bitset < nx > viz;
int nc,n,m;
void dfs (int nod)
{
    viz.set(nod);
    for(vector < int > :: iterator it=v[nod].begin(); it!=v[nod].end(); it++)
        if(viz.test(*it)==false)
            dfs(*it);
}
int main()
{
    in>>n>>m;
    for(;m;m--)
    {
        int i,j;
        in>>i>>j;
        v[i].push_back(j);
        v[j].push_back(i);
    }
    for(int i=1; i<=n; i++)
        if(viz.test(i)==false)
    {
        nc++;
        dfs(i);
    }
    out<<nc;
    return 0;
}