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 = "# -*- coding: utf-8 -*-\nimport bisect\nimport heapq\nimport math\nimport random\nimport sys\nfrom collections import Counter, defaultdict, deque\nfrom decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal\nfrom functools import lru_cache, reduce\nfrom itertools import combinations, combinations_with_replacement, product, permutations\nfrom operator import add, mul, sub\n\nsys.setrecursionlimit(100000)\ninput = sys.stdin.readline\nINF = 2**62-1\n\n\ndef read_int():\n    return int(input())\n\n\ndef read_int_n():\n    return list(map(int, input().split()))\n\n\ndef read_float():\n    return float(input())\n\n\ndef read_float_n():\n    return list(map(float, input().split()))\n\n\ndef read_str():\n    return input().strip()\n\n\ndef read_str_n():\n    return list(map(str, input().split()))\n\n\ndef error_print(*args):\n    print(*args, file=sys.stderr)\n\n\ndef mt(f):\n    import time\n\n    def wrap(*args, **kwargs):\n        s = time.time()\n        ret = f(*args, **kwargs)\n        e = time.time()\n\n        error_print(e - s, 'sec')\n        return ret\n\n    return wrap\n\n\n@mt\ndef slv(S):\n    N = len(S)\n    if S[N-1] == '1':\n        print(-1)\n        return -1\n\n    if S[0] != '1':\n        print(-1)\n        return -1\n\n    if S[N-2] != '1':\n        print(-1)\n        return -1\n\n\n    for i in range(N//2):\n        if S[i] != S[N-2-i]:\n            print(-1)\n            return -1\n\n    p = [N]\n    for i in range(N, 0, -1):\n        if S[i-1] == '1':\n            p.append(i)\n        else:\n            p.append(p[-1])\n    p.reverse()\n    e = []\n    for i in range(1, N):\n        e.append((i, p[i]))\n\n    for u, v in e:\n        print(u, v)\n\n\ndef main():\n    S = read_str()\n    (slv(S))\n\n\ndef __starting_point():\n    main()\n\n__starting_point()"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: 16177