#Democracy in Danger
#Written on October 21, 2017
#Author Amjad

from math import sqrt

group = 0
b = []
votes = 0
while True:
    try:
        group =  int(input())
        b = ([int(a) for a in input().split()])
        b.sort()
    except EOFError:
        for i in range(0, round( (group +1) / 2)):
            votes += (int(b[i]) + 1) / 2
        print(int(votes))
        break

Edited by author 21.10.2017 22:42