#include<cstdio>
#include<vector>
#define NMAX 100001
using namespace std;
vector<int> v[NMAX];
int ok[NMAX];
int n,m,ct=0;
void dfs(int nod)
{
ok[nod]=1;
vector<int>::iterator it;
for(it=v[nod].begin();it!=v[nod].end();++it)
	if(!ok[*it]) dfs(*it);
return;
}
int main()
{
freopen("dfs.in","r",stdin);
freopen("dfs.out","w",stdout);
scanf("%d%d",&n,&m);
int x,y,i;
for(i=1;i<=m;i++)
{
scanf("%d%d",&x,&y);
 v[x].push_back(y);
 v[y].push_back(x);
}

for(i=1;i<=n;i++)
if(!ok[i])
{
ct++;
dfs(i);
}
printf("%d\n",ct);
return 0;
}