#include<stdio.h>
long int t[100000],viz[100000],sol,i,j,x,y,n,m;
int main()
{	FILE *f=fopen("dfs.in","r"),
         *g=fopen("dfs.out","w");
	fscanf(f,"%ld%ld",&n,&m);
   for(i=1;i<=n;i++) t[i]=i;
	for(i=1;i<=m;i++)
	{ fscanf(f,"%ld%ld",&x,&y);
	  if(t[x]!=t[y]) for(j=1;j<=n;j++) if(t[j]==t[y]) t[j]=t[x];
	}
	for(i=1;i<=n;i++)
	 if(!viz[t[i]]){ sol++; viz[t[i]]=1;}
	fprintf(g,"%ld",sol);
	fcloseall();
	return 0;

}