f = open('input.txt', 'r')
line = f.readlines()[1]
f.close()

n, k = -1, 0
c = 1
count = 0

for i in range(len(line) - 1, -1, -1):

    n += 1
    if line[i] == '1':
        k += 1

    if n < k:
        continue

    if (line[i] == '1') and (k > 0):
        c = c * n // k
        count += c
    elif n > k:
        c = c * n // (n - k)

f = open('output.txt', 'w')
f.write(bin(count)[2:])
f.close()