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;
typedef long long ll;
typedef pair<int,int> P;
int main(){
	string s;cin>>s;
	int n=s.length();
	if(s[0]!='1'||s[n-1]!='0'){
		cout<<-1<<endl;
		return 0;
	}
	bool f=true;
	for(int i=0;i<n/2;i++){
		if(s[i]!=s[n-i-2])f=false;
	}
	if(!f){
		cout<<-1<<endl;
		return 0;
	}
	int id=2;
	cout<<1<<" "<<2<<endl;
	for(int i=1;i<n/2;i++){
		cout<<id<<" "<<i+2<<endl;
		if(s[i]=='1'){
			id=i+2;
		}
	}
	for(int i=n/2+1;i<n;i++){
		cout<<id<<" "<<i+1<<endl;
	}
}