import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Scanner;


public class DemocracyInDanger {

    private static int sum = 0;
    private static int i=0;

    public static void main(String[] args) {
        try {
            BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
            int amount = Integer.parseInt(in.readLine());
            if(amount>=1 && amount<=101 && amount%2!=0){
                int[] party = new int[amount];
                Scanner scanner = new Scanner(System.in);
                while(i<amount){
                    party[i]=scanner.nextInt();
                    if(party[i]>0 && party[i]%2!=0){
                        sum+=party[i];
                    }else    throw new IOException();
                    i++;
                }
                if (sum<=9999){
                    sum=0;
                    Arrays.sort(party);
                    for (int i = 0; i <=amount/2; i++) {
                        sum +=party[i]/2+1;
                    }
                    System.out.println(sum);
                }
            }

        } catch (Exception e) {
        }
    }

}