#include<fstream.h>

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

typedef struct nod
{
 int inf;
 nod * urm;
} *pNod;

pNod v[100002];
int viz[100002],n,i,j,m,contor;
void add(pNod & prim, int val)
{
nod *p;
p=new nod;
p->inf=val;
p->urm=prim;
prim=p;
}
void dfs(int x)
{ pNod j;
 viz[x]=1;
 for(j=v[x];j;j=j->urm)
  if(!viz[j->inf])
  dfs(j->inf);
}
int main()
{ int x,y;
 f>>n>>m;
 for(i=1;i<=m;i++)
 {
  f>>x>>y;
  add(v[x],y);
  add(v[y],x);
 }
 for(i=1;i<=n;i++)
  if(!viz[i])
  {
   contor++;
   dfs(i);
  }
 g<<contor;
 return 0;
}