#include <fstream>

using namespace std;
ifstream in ("dfs.in");
ofstream out ("dfs.out");
struct nod {int inf; nod *next;} *L[100001];
int n,m,used[100001],st[100001],k;
void ins(nod *&first , int inf)
{
    nod *p = new nod;
    p->inf = inf;
    p->next = first;
    first = p;
}
void l()
{
    for(int i=1;i<=k;i++)
    {
        nod *p=new nod;
        p=L[st[i]];
        while(p!=0)
        {
            int current_nod = p->inf;
            if(used[current_nod]==0)
            {
                st[++k]=current_nod;
                used[current_nod]++;
            }
            p=p->next;
        }
    }
}
int main()
{
    in>>n>>m;
    for(int i(1);i<=m;i++)
    {
        int x,y;
        in>>x>>y;
        ins(L[x],y);
        ins(L[y],x);
    }
    if(m==0)
    {
       out<<n;
       return 0;
    }
    k=1;
    st[k]=1;
    l();
    int Y=1;
    for(int i(1);i<=n;i++)
    {
        if(L[i]!=0){
            if(used[i]==0)
            {
                Y++;
                k=1;
                st[k]=i;
                l();
            }
        }
        else Y++;
    }
    out<<Y;
    return 0;
}