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

int M[2*N][2],len[N], n, m;
int *a[N];
bool use[N];

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