Problem: You are given a string s of length n. Does a tree with n vertices that satisfies the following conditions exist?

* The vertices are numbered 1,2,..., n.
* The edges are numbered 1,2,..., n-1, and Edge i connects Vertex u_i and v_i.
* If the i-th character in s is `1`, we can have a connected component of size i by removing one edge from the tree.
* If the i-th character in s is `0`, we cannot have a connected component of size i by removing any one edge from the tree.



If such a tree exists, construct one such tree.

Constraints

* 2 \leq n \leq 10^5
* s is a string of length n consisting of `0` and `1`.

Input

Input is given from Standard Input in the following format:


s


Output

If a tree with n vertices that satisfies the conditions does not exist, print `-1`.

If a tree with n vertices that satisfies the conditions exist, print n-1 lines. The i-th line should contain u_i and v_i with a space in between. If there are multiple trees that satisfy the conditions, any such tree will be accepted.

Examples

Input

1111


Output

-1


Input

1110


Output

1 2
2 3
3 4


Input

1010


Output

1 2
1 3
1 4

Solution (in PYTHON3):

Solution:

s = input()
len_s = len(s)

if s[-1] == "1":
	print(-1)
	exit()
for i in range((len_s - 1)//2):
	if s[i] != s[len_s - 2 - i]:
		print(-1)
		exit()
if s[0] != '1':
	print(-1)
	exit()

num = 1
for i in range(len_s - 1):
	if s[i] == '1':
		print('{0} {1}'.format(num, i + 2))
		num = i + 2
	else:
		print('{0} {1}'.format(num, i + 2))