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

int main(){
	string s;
	cin >> s;
	int n=s.size();
	bool flag=false;
	
	if(s[0]=='0')flag=true;
	if(s[n-1]=='1')flag=true;
	for(int i=1;i<n-1;i++){
		int j=n-2-i;
		if(s[i]!=s[j])flag=true;
	}
	
	if(flag){
		cout << "-1" << endl;
		return 0;
	}
	
	s[n-1]='1';
	int min1=n-1;
	for(int i=n-2;i>=0;i--){
		cout << i+1 << " " << min1+1 << endl;
		if(s[i]=='1')min1=i;
	}
	return 0;
}
### Prompt

Construct a Cpp code solution to the problem outlined:

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

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;

int main(){
	string s;
	cin >> s;
	int n=s.size();
	bool flag=false;
	
	if(s[0]=='0')flag=true;
	if(s[n-1]=='1')flag=true;
	for(int i=1;i<n-1;i++){
		int j=n-2-i;
		if(s[i]!=s[j])flag=true;
	}
	
	if(flag){
		cout << "-1" << endl;
		return 0;
	}
	
	s[n-1]='1';
	int min1=n-1;
	for(int i=n-2;i>=0;i--){
		cout << i+1 << " " << min1+1 << endl;
		if(s[i]=='1')min1=i;
	}
	return 0;
}
```