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 = 'import typing\nimport sys\nimport math\nimport collections\nimport bisect\nimport itertools\nimport heapq\nimport decimal\nimport copy\nimport operator\n\n# sys.setrecursionlimit(10000001)\nINF = 10 ** 20\nMOD = 10 ** 9 + 7\n# MOD = 998244353\n# buffer.readline()\n\n\ndef ni(): return int(sys.stdin.readline())\ndef ns(): return list(map(int, sys.stdin.readline().split()))\ndef na(): return list(map(int, sys.stdin.readline().split()))\ndef na1(): return list([int(x)-1 for x in sys.stdin.readline().split()])\n\n\n# ===CODE===\ndef main():\n    s = input()\n\n    if s[0] == "0" or s[-1] == "1":\n        print((-1))\n        return()\n\n    s = s[:-1]\n    n = len(s)\n    for i in range(n):\n        if s[i] != s[n-1-i]:\n            print((-1))\n            return\n\n    pool = []\n    idx = 0\n    for i in range(1, n):\n        if s[i] == "1":\n            print((idx+1, i+1))\n            idx = i\n            for pi in pool:\n                print((idx+1, pi+1))\n            pool = []\n        else:\n            pool.append(i)\n    print((n, n+1))\n\n\ndef __starting_point():\n    main()\n\n__starting_point()'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: 177269