#include <bits/stdc++.h>
#define sp ' '
#define nyan "(=^・ω・^=)"
#define mkp make_pair
#define lP pair<ll,ll>
#define iP pair<int,int>

typedef long long ll;
using namespace std;
const int mod = 1e9 + 7;

int N, A[100], cnt, s;

int main(){
	cin >> N;
	for (int i = 0; i != N; ++i) {
		cin >> A[i];
		s += A[i];
	}
	if (s % 2 == 0) {
		cout << s / 2 << endl;
		return 0;
	}
	sort(A, A + N);
	for (int i = 0; i != N; ++i) {
		if (A[i] & 1 == 1) {
			cout << (s - A[i]) / 2 << endl;
			return 0;
		}
	}
	return 0;
}
