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.

-----Sample Input-----
1111

-----Sample Output-----
-1

It is impossible to have a connected component of size n after removing one edge from a tree with n vertices.

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

ns = {"__name__": "__main__"}
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "def main():\n    S = list(input())\n\n    N = len(S)\n\n    if (S[0] == '0') or (S[-1] == '1'):\n        print (-1)\n        return 0\n\n    lst = []\n    for i in range((N - 1) // 2):\n        if S[i] != S[N - 2 - i]:\n            print (-1)\n            return 0\n        if S[i] == '1':\n            lst.append(i + 1)\n    if N % 2 == 0 and S[N//2 - 1] == '1':\n        lst.append(N//2)\n    # print (lst)\n\n    if lst[-1] * 2 != N:\n        center = lst[-1] + 1\n        for x in range(lst[-1] * 2 + 2, N + 1):\n            print (center, x)\n\n        before = 1\n        n = lst[-1] * 2 + 2\n        tmp = 1\n        for tmp in lst[1:]:\n            print (before, tmp)\n            print (n - before, n - tmp)\n            for x in range(tmp - before - 1):\n                print (before + 1 + x, tmp)\n                print (n - (before + 1 + x), n - tmp)\n            before = tmp\n        print (tmp, center)\n        print (n - tmp, center)\n\n    if lst[-1] * 2 == N:\n        before = 1\n        n = lst[-1] * 2 + 1\n        tmp = 1\n        for tmp in lst[1:]:\n            print (before, tmp)\n            print (n - before, n - tmp)\n            for x in range(tmp - before - 1):\n                print (before + 1 + x, tmp)\n                print (n - (before + 1 + x), n - tmp)\n            before = tmp\n        print (tmp, n - tmp)\n\ndef __starting_point():\n    main()\n__starting_point()"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: 14833