#include<fstream>
#include<queue>
using namespace std;

struct nod
{
    int val;
    nod *next;
};

class Lista
{
    nod *head, *last, *current;
public:
    Lista(){head=last=NULL; current=head;}
    void push(int x);
    bool empty(){return head==NULL;}
    int getCurrentValue(){return current->val;}
    nod* getCurrentPointer(){return current;}
    void increaseCurrentPointer(){current=current->next;}
    void resetCurrentPointer(){current=head;}
};

void Lista::push(int x)
{
    if(head==NULL)
    {
          head=new nod;
          head->val=x;head->next=NULL;
          last=head;
          current=head;
    }
    else
    {
          nod *p=new nod;
          p->val=x;p->next=NULL;
          last->next=p; last=p;
    }
}

ifstream f("dfs.in");
ofstream g("dfs.out");

int n,m,i,x,y,aux,componente_conexe;
Lista vec[100001];
bool verif[100001];

void dfs(int x)
{
 //   g<<'\n';
    verif[x]=1;
    for( ;vec[x].getCurrentPointer()!=NULL; vec[x].increaseCurrentPointer())
    {
        aux=vec[x].getCurrentValue();
        if(!verif[aux])
            {/*g<<aux+1<<" "*/;dfs(aux);}
    }
    vec[x].resetCurrentPointer();
}

int main()
{
    f>>n>>m;
    for(i=0;i<m;i++)
    {
       f>>x>>y;
       vec[x-1].push(y-1);
       vec[y-1].push(x-1);
    }
    for(i=0;i<n;i++)
        if(!verif[i])
          {dfs(i);componente_conexe++;}

    g<<componente_conexe;
}