#include <bits/stdc++.h>

using namespace std;
ifstream fin ("dfs.in");
ofstream fout ("dfs.out");
int x, y, n, m, k;
vector <int> v[1000000];
int viz[10000000];
void citire()
{
    fin>>n>>m;
    for (int i=1; i<=m; i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}
void DFS(int nod)
{
    for(auto it : v[nod])
        if (!viz[it])
    {
        viz[it]=1;
        DFS(it);
    }
}
void calculare()
{
    for(int i=1;i<=n;i++)
    {
        if(viz[i]==0)
            {
            DFS(i);
            k++;
            }
    }
}
int main()
{
    citire();
    calculare();
    fout<<k;
    return 0;
}