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>
#define ll long long

using namespace std;

int n;
string s;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin>>s;
	int n=s.size();
    if(s[0]!='1' || s[n-1]!='0')
    {
        cout<<-1;
        return 0;
    }

    int m=n-2;
    for(int i=1;i<=m/2;i++)
        if(s[i]!=s[m-i])
        {
            cout<<-1;
            return 0;
        }

    int posl=1;
    for(int i=2;i<=n;i++)
    {
        cout<<posl<<" "<<i<<endl;
        if(s[i-2]=='1')
            posl=i;
    }

	return 0;
}