//include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <climits>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <queue>
#include <random>
#include <complex>
#include <regex>

using namespace std;

#define SHOW_VECTOR(v) {std::cerr << #v << "\t:";for(const auto& xxx : v){std::cerr << xxx << " ";}std::cerr << "\n";}
#define SHOW_MAP(v){std::cerr << #v << endl; for(const auto& xxx: v){std::cerr << xxx.first << " " << xxx.second << "\n";}}


int main() {

    int N;
    cin >> N;

    vector<int> A(N);
    for (int i = 0; i < N; i++)cin >> A[i];

    int sum = 0;
    vector<int> odd;
    for (int i = 0; i < N; i++) {
        if (A[i] & 1) odd.push_back(A[i]);
        if (!(A[i] & 1)) sum += A[i];
    }

    sort(odd.begin(), odd.end());
    sum += accumulate(odd.begin(), odd.end(), 0);
    if (odd.size() & 1) sum -= odd.front();

    cout << sum / 2 << endl;

}










