#include <iostream>

using namespace std;

int main()
{
    int n,nr,i,suma=0,k=0;
    cout<<"n=";
    cin>>n;
    for(i=1;i<=n;i++){
        cout<<"nr=";
        cin>>nr;
        nr>0?(k=k+1,suma=suma+nr):(k=0,suma=0);
        if(k==3) cout<<"Media aritmetica="<<(float)suma/3<<'\n';
    }
    return 0;
}