#include <fstream>
#include <vector>
#define nmax 100002
using namespace std;

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

vector <int> v[nmax];
int n,m,c,viz[nmax];

inline void citire ()
{
    int x,y;
    fin>>n>>m;
    for (int i=1;i<=m;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

inline void dfs (int x)
{
    viz[x]=1;
    for (int i=0;i<v[x].size();i++)
        if (viz[v[x][i]]!=1)
            dfs(v[x][i]);
}

int main()
{
    citire();
    for (int i=1;i<=n;i++)
        if (viz[i]!=1)
        {
            c++;
            dfs(i);
        }
    fout<<c;
    return 0;
}