#include<iostream> using namespace std; int main(){ int n,b[100]; double a; cin>>n; for(int i=1;i<=n;i++){ cin>>b[i]; a+=b[i]; } a/=n; printf("%.1f\n",a); for(int i=1,f=0;i<=n;i++){ if(b[i]>a){ if(++f>1) cout<<" "; cout<<i<<":"<<b[i]; } } cout<<endl; return 0; }