#include<iostream>
#include<algorithm>
#include<iomanip>

using namespace std;

struct waiting{
	int ord,wait,wsum;
}a[1145000];

bool cmp(waiting a,waiting b){
	return a.wait<b.wait;
}

int main(){
	int n,cnt;
	a[0].wsum=0;
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i].wait;
		a[i].ord=i;
	}
	sort(a+1,a+n+1,cmp);
	for(int i=1;i<=n;i++){
		cout<<a[i].ord<<" ";
	}
	cout<<endl;
	for(int i=1;i<=n;i++){
		a[i].wsum=a[i-1].wsum+a[i].wait;
		cnt+=a[i].wsum-a[i].wait;
	}
	cout<<fixed<<setprecision(2)<<(double)cnt/n;
}

16行开long long 全WA