import heapq
N = int(input())
heap = sorted(list(map(int,input().split())))
hmax = heap[-1]
kmax = 0
while 1<<kmax<=hmax:
    kmax += 1
low = N-1
high = N+kmax
while high-low>1:
    heap0 = heap[:]
    M0 = len(heap0)
    mid = (high+low)//2
    cnt = 0
    for i in range(mid):
        if M0==0:break
        cnt += 1
        heap1 = []
        M1 = 0
        M2 = M0
        for _ in range(M2):
            h = heapq.heappop(heap0)
            M0 -= 1
            if h>>i & 1:
                h -= 1<<i
                if h>0:
                    heapq.heappush(heap1,h)
                    M1 += 1
                break
            if h%(1<<i)>0:
                h -= 1<<i
                if h>0:
                    heapq.heappush(heap1,h)
                    M1 += 1
                break
            heapq.heappush(heap1,h)
            M1 += 1
        heap0 += heap1
        heapq.heapify(heap0)
        M0 += M1
    if M0==0:
        high = mid
    else:
        low = mid
print(high)