// dfs-componente conexe int*[] cu realloc
#include <cstdio>
#include <cstdlib>
#define N 100001

int *a[N];
int n, m;
bool use[N];
int len[N];

void read()
{
	freopen("dfs.in","r",stdin);
	
	int p, q;
	scanf("%d %d\n", &n, &m);
	
	for(int i=1;i<=n;++i) a[i]=new int[2];
	
	while(m--)
	{
		scanf("%d %d\n", &p, &q);
		
		a[p]=(int*)realloc(a[p], sizeof(int)*(len[p]+2));
		a[q]=(int*)realloc(a[q], sizeof(int)*(len[q]+2));
		
		a[p][len[p]++]=q;
		a[q][len[q]++]=p;
	}
	
	for(int i=1;i<=n;++i) a[i][len[i]]=0;
}


inline void dfs(int n)
{
	use[n]=1;
	
	for(int *i=a[n]; *i; ++i)
		if(!use[*i])
			dfs(*i);
}

int main()
{
	read();
	int i, sol=0;
	
	for(i=1;i<=n;++i)
		if(!use[i])
		{
			++sol;
			dfs(i);
		}
	
	freopen("dfs.out","w",stdout);
	printf("%d\n", sol);
	return 0;
}