n = int(input())
a = input()
z = 1
c = 0
y = 0
if a[-1] == '0':
print('-1')
exit()
for i in a:
if i == '1':
if y == 0:
print(z,end=' ')
else:
print(c,end=' ')
y = 0
z -= 1
else:
if y == 0:
c = z
z += 1
print(z,end=' ')
y = 1
else:
print(z,end=' ')
z += 1

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