//通过映射的方法对每一位的数进行交换
include [HTML_REMOVED]
include [HTML_REMOVED]
using namespace std;
const int N = 1e4+10;
typedef long long LL;
int a[N],b[N],c[N];
int n;
int main()
{
int ans=0;
cin>>n;
for(int i=1;i<=n;i)cin>>a[i];
for(int i=1;i<=n;i)
{
b[a[i]]=i;
c[i]=a[i];
}
for(int i=1;i<=n;i)
{
if(b[i]!=i)
{
int t1=b[i],t2=c[i];
swap(b[i],b[c[i]]);
c[i]=i;
c[t1]=t2;
ans;
}
}
cout<<ans;
}