k=int(input())
a=[]
for i in input().split():
    a.append(int(i))
zh=0
def sort(a):
    n = len(a)
    for i in range(n-1):
        k=i
        for j in range(i+1,n):
            if a[k]>a[j]:
                k=j
        a[i],a[k]=a[k],a[i]
    return a[:len(a)//2+1]
a=sort(a)
for i in range(len(a)):
    zh+=a[i]//2+1
print(zh)