python3 双指针
n = int(input())
a = input()
w = [int(i) for i in a.split()]
sum = [0 for i in range(100010)]
j = 0
t = 0
res = 0
for i in range(n):
if(i >= (2**(j+1) - 1)):
j += 1
sum[j] += w[i]
for i in range(100010):
if sum[i] > res:
res = sum[i]
t = i
print(t+1)