# include <fstream>

using namespace std;

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

int N,M,viz[100005],c;

typedef struct nod
{
 int x;
 nod *y;
} *qnod;

qnod v[100005];

void adaugare(qnod &dest, int val)
{
qnod q;
q = new nod;
q->x=val;
q->y=dest;
dest=q;
}

void citire()
{
f>>N>>M;
int i,a,b;
for (i=1;i<=M;i++)
{
f>>a>>b;
adaugare(v[a],b);
adaugare(v[b],a);
}
f.close();
}

void DFS(int nod)
{
qnod q;
viz[nod]=1;
for (q=v[nod]; q!=NULL; q=q->y)
if(viz[q->x]==0)
DFS(q->x);
}

int main()
{
citire();
int i;
for (i=1;i<=N;i++)
if(viz[i]==0)
{
c++;
DFS(i);
}
g<<c;
g.close();
return 0;
}