#include <bits/stdc++.h>
using namespace std;
int main(void){
    int n,sum=0,count=0,pt=0;
    cin>>n;
    int *a = new int[n];
    for(int i=0;i<n;i++){
        cin>>a[i];
        if(a[i]%2==0){
            sum+=a[i];
        }else{
            count+=1;
        }
    }
    for(int i=0;i<n;i++){
        if(a[i]%2==1){
            pt+=1;
            sum+=a[i];
            if(pt==1){
                a[0]=a[i];
            }
            if(a[0]>a[i]){
                a[0]=a[i];
            }
        }
    }
    if(count%2==0){
        cout<<sum/2<<endl;
    }else{
        cout<<(sum-a[0])/2<<endl;
    }
}
