#include<stdio.h>
int N,M,A[50][50],s[50],nr;
void constr(int A[50][50],int &N,int &M)
{
	freopen("date.in","r",stdin);
	freopen("date.out","w",stdout);
	scanf("%d%d",&N,&M);
	int i,j;
	while(scanf("%d%d",i,j))
		A[i][j]=A[j][i]=1;
}
void DFS(int nod)
{
	int i;
	s[nod]=1;
	for(i=1;i<=N;i++)
		if(A[nod][i]==1&&s[i]==0)
			DFS(i);
}
int main()
{
	constr(A,N,M);int i;
	for(i=1;i<=N;i++)
		if(!s[i])
		{nr++;DFS(i);}
	printf("%d",nr);
	return 0;
}