Problem: 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.

Examples

Input

1111


Output

-1


Input

1110


Output

1 2
2 3
3 4


Input

1010


Output

1 2
1 3
1 4

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;

int main(int argc, char const *argv[])
{
	string s;
	cin>>s;
	int n=s.size();
	if (s[0]=='0'||s[n-1]=='1')
	{
		cout<<"-1\n";
		return 0;
	}
	int f=1;
	for (int i = 0; i < n/2; ++i)
	{
		if (s[i]!=s[n-i-2])
		{
			f=0;
		}
	}
	if (f==0)
	{
		cout<<"-1\n";
		return 0;
	}
	int now=n;
	for (int i = n-1; i > 0; --i)
	{
		cout<<i<<" "<<now<<endl;
		if (s[i-1]=='1')
		{
			now=i;
		}
	}
	return 0;
}