length = int(input())
list = tuple(input().split())
set = set(list)
newList = []
result = 0

for i in set:
    newList.append(list.count(i))
newList = sorted(newList)
while len(newList) > 0:
    max = newList[len(newList)-1]
    temp = newList[0]
    maxTemp = (temp, 0 , 1)
    temp1 = 0
    temp2 = 1
    notDeleted = True
    if len(newList) > 1:
        while temp2 <= len(newList):
            if temp == max-1:
                newList.remove(max)
                for i in range(temp1, temp2):
                    newList.remove(newList[i])
                notDeleted = False
                result += 1
                break
            elif temp < max-1:
                if temp > maxTemp[0]:
                    maxTemp = (temp, temp1, temp2)
                temp += newList[temp2]
                temp2 += 1
            else:
                temp -= newList[temp1]
                temp1 += 1
        if notDeleted:
            for i in range(temp1, temp2):
                newList.remove(newList[i])
            newList.remove(max)
            result += 1
    else:
        result += 1
        break
print(result)