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 = '\n\ndef I(): return int(input())\ndef MI(): return list(map(int, input().split()))\ndef LI(): return list(map(int, input().split()))\n\n\n"""\ni=1は絶対ok．葉を繋ぐ辺を取れば良い\ni=NはNG．もともとN要素なので\nこれ，i=0の時ngという条件を足せば，左右対象ぽい．サイズがaとN-aができるため．\n\n「らしい」必要条件が分かった．必要十分だと嬉しい．\nO(N)に近い感じで解きたいので，順次構築していくイメージ．\n\n"""\ndef main():\n    mod=10**9+7\n    S=input()\n    N=len(S)\n    \n    if S[0]=="0" or S[-1]=="1":\n        print((-1))\n        return\n    \n    S=S[:-1]\n    flag=1\n    for i in range(N-1):\n        if S[i]!=S[-1-i]:\n            flag=0\n            \n    if flag==0:\n        print((-1))\n        return\n    \n    L=[(1,2)]\n    head=2\n    now=3\n    for s in S[1:]:\n        L.append((head,now))\n        if s=="1":\n            head=now\n        now+=1\n    \n    for a in L:\n        print((\' \'.join(map(str, a))))\n        \n\nmain()\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: 14169