#include <fstream>

int n,m,viz[100005],cnt=0;
ifstream cin("dfs.in");
ofstream cin("dfs.out");
using namespace std;
typedef struct nod
{
    int x;
    nod *a;
}*pnod;

pnod v[100005];
void add(pnod &dest, int val)
{
    pnod p=new nod;
    p->x=val;
    p->a=dest;
    dest=p;
}
void citire()
{
    int x,y;
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        cin>>x>>y;
        add(v[x],y);
        add(v[y],x);
    }
}
void dfs(int k)
{
    pnod p=new nod;
    viz[k]=1;
    for(int p=v[k];p!=NULL;p=p->a)
        if(viz[p->x]==0)
            dfs(p->x);
}
int main()
{
    citire();
    for(int i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            cnt++;
            dfs(i);
        }
    }
    cout<<cnt;
    return 0;
}