#include <fstream>
#include <vector>
using namespace std;
ifstream cin("dfs.in");
ofstream cout("dfs.out");
vector< vector <int>> edges;
vector <bool> viz;
int n,m;
void readgraph()
{
    cin>>n>>m;
    edges.resize(n);
    viz.resize(n);
    for(int i=0;i<m;i++)
    {
        int a,b;
        cin>>a>>b;
        a--;
        b--;
        edges[a].push_back(b);
        edges[b].push_back(a);
    }
}
void dfs(int node)
{
    viz[node]=1;
    for(auto next: edges[node])
        if(!viz[next])
        dfs(next);
}
int main()
{
    readgraph();
    int c=0;
    for(int i=0;i<edges.size();i++)
            if(!viz[i])
                dfs(i),c++;
    cout<<c;
    return 0;
}