#include <stdio.h>
#include <stdlib.h>
#define MAXN 7000000
int fa[MAXN], rank[MAXN];
int find(int x)
{
	if(x==fa[x]){
		return x;
	}else{
		fa[x]=find(fa[x]);
		return fa[x];
	}
	 
}
void merge(int i, int j)
{
    int x = find(i), y = find(j);
    if(x==y) return; 
    if (rank[x] < rank[y])
        fa[x] = y;
    else if(rank[x] > rank[y])
        fa[y] = x;
    else{
    	fa[y] = x;
    	rank[x]++;
	}

}
int main()
{
     int T,n,m,u,v,i,sum;
     sum=0;
     scanf("%d%d",&n,&m);
     for(i=1;i<=n;i++)
     {
         fa[i]=i;
         }
     for(i=0;i<=m-1;i++)
     {
         scanf("%d%d",&u,&v);
         merge(u,v);
         }
     for(i=1;i<=n;i++)
     {
         if(fa[i]==i)
         {
             sum++;
             }
         }
     printf("%d\n",sum);
     return 0;
}