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:
# -*- coding: utf-8 -*-
from sys import stdin

s_in = lambda: stdin.readline()[:-1] # s = s_in()
d_in = lambda: int(stdin.readline()) # N = d_in()
ds_in = lambda: list(map(int, stdin.readline().split())) # List = ds_in()

S = s_in()
N = len(S)

if S[0] == '0':
    print(-1)
    exit()
elif S[-1] == '1':
    print(-1)
    exit()

for i in range((N-1)//2):
    if S[i] != S[-i-2]:
        print(-1)
        exit()

parent = N
for i in range(N-1, 0, -1):
    s = S[i-1]
    if s == '1':
        print(i, parent)
        parent = i
    else:
        print(i, parent)