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 sys\nimport math\nfrom collections import defaultdict\nfrom bisect import bisect_left, bisect_right\n\nsys.setrecursionlimit(10**7)\ndef input():\n    return sys.stdin.readline()[:-1]\n\nmod = 10**9 + 7\n\ndef I(): return int(input())\ndef LI(): return list(map(int, input().split()))\ndef LIR(row,col):\n    if row <= 0:\n        return [[] for _ in range(col)]\n    elif col == 1:\n        return [I() for _ in range(row)]\n    else:\n        read_all = [LI() for _ in range(row)]\n        return map(list, zip(*read_all))\n\n#################\n\ns = list(input())\nn = len(s)\n\nfor i in range((n-1)//2+1):\n    if s[i] != s[n-2-i]:\n        print(-1)\n        return\n\nif s[0] == '0':\n    print(-1)\n    return\n\nif s[n-1] == '1':\n    print(-1)\n    return\n\nfrom_ = 1\nto_ = 2\nans = []\nfor i in range(n-1):\n    ans.append((from_,to_))\n    if s[i] == '1':\n        from_ = to_\n        to_ += 1\n    else:\n        to_ += 1\n\nfor a in ans:\n    print(*a)"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: