#include<bits/stdc++.h> using namespace std; int n,a[101],sum; int main(){ double sum,ans; cin>>n; for(int i=1;i<=n;i++){ cin>>a[i]; sum+=a[i]; } ans=sum/n; printf("%.1lf",ans); cout<<endl; for(int i=1;i<=n;i++){ if(a[i]>ans) cout<<i<<":"<<a[i]<<" "; } return 0; }