#include<stdio.h>

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

lista a[100009];

int fol[100009],i,j,n,x,y,m;

void insert(lista &prim,int x)
{ 
	lista p=new nod;
	p->inf=x;
	p->urm=prim;
	prim=p;
}

void dfs(int i)
{ 
	lista p=a[i];
	fol[i]=1;
    for(;p;p=p->urm) if(!fol[p->inf]) dfs(p->inf);
} 	

int main()
{ 
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	
	scanf("%d %d",&n,&m);
	
	for(i=1;i<=m;i++) { scanf("%d %d",&x,&y);
	                    insert(a[x],y);
	                    insert(a[y],x);
					  }
	
	for(i=1;i<=n;i++) if(!fol[i]) { j++;
	                                dfs(i);
	                              }

    printf("%d\n",j);

    fclose(stdin);
    fclose(stdout);
	
	return 0;
}