#include <fstream>

using namespace std;

ifstream cin("dfs.in");
ofstream cout("dfs.out");

int n,m;
int mc[400001],nr;
int urm[400001];
int lst[200001];
bool viz[200001];

void dfs(int x)
{
    viz[x]=1;

    for(int i=lst[x];i!=0;i=urm[i])
        if(!viz[ mc[i] ])
            dfs(mc[i]);
}

void adauga(int x,int y)
{
    mc[++nr]=y;
    urm[nr]=lst[x];
    lst[x]=nr;
}

int main()
{
    cin>>n>>m;
    for(int i,j,k=1;k<=m;k++)
    {
        cin>>i>>j;

        adauga(i,j);
        adauga(j,i);
    }

    int nr=0;
    for(int i=1;i<=n;i++)
        if(!viz[i])
        {
            nr++;
            dfs(i);
        }

    cout<<nr;
}