#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

signed main()
{
    int n;
    cin >> n;
    vector<int> a(n);
    int c = 0;
    int aaaa = 1e9;
    for(auto& x : a){
        cin >> x;
        if(x % 2){
            ++c;
            aaaa = min(aaaa, x);
        }
    }
    int sum = accumulate(a.begin(), a.end(), 0);
    if(c % 2 == 0){
        cout << sum / 2 << endl;
    }else{
        cout << (sum - aaaa) / 2 << endl;
    }
}


