#include<fstream>
using namespace std;
int n,m,i,k=0,v[100005],c,h;
ifstream f("dfs.in");
ofstream g("dfs.out");
typedef struct nod
{int a;
nod *b;} *NOD;
NOD v1[100005];
void put(int q,NOD &go)
{NOD z;
z=new nod;
z->a=q;
z->b=go;
go=z;}
void df(int l)
{NOD p;
v[l]=1;
for(p=v1[l];p!=NULL;p=p->b) 
if(!v[p->a]) 
df(p->a);}	
int main()
{f>>n;
f>>m;
for(i=1;i<=m;i++)
{f>>c;
f>>h;
put(h,v1[c]);
put(c,v1[h]);}
f.close();
for(i=1;i<=n;i++)
if(v[i]==0) 
{k++; 
df(i);}
g<<k;
g.close();
return 0;}