Taxi

#include <iostream>
using namespace std;

int main()
{
    int n,sum;

    cin>>n;

    int s[n];

    for(int i=0;i<n;i++)
    {
        cin>>s[i];
        sum = sum + s[i];

    }

    if(sum%4 == 0)
    {
        cout<<sum/4;
    }
    else
    {
        cout<<(sum/4)+1;
    }

}