#include <iostream>

using namespace std;

int main()
{
    int v[20],i,n,SA=0,c=0,nr=0;
    float MA;
    cout<<"n="; cin>>n;
    for (i=1;i<=n;i++)
    {
        cout <<"introduceti numere ";
        cin >> v[i];
        if ( i%2 == 1)
        {SA=SA+ v[i];
        nr=nr++;
        }
    }
    MA=SA/nr;
    cout<<"Media aritmetica este... "<<MA;

    return 0;
}