#include <iostream>
#include <string>

using namespace std;
int main(){
	int i,n;
	string s;
	cin >> s;
	n = s.size();
	if(s[0]=='0' || s[n-2]=='0' || s[n-1]=='1'){
		cout << -1 << endl;
		return 0;
	}
	for(i=0;i<n-1;i++){
		if(s[i]!=s[n-2-i]){
			cout << -1 << endl;
			return 0;
		}
	}
	int x = 1;
	for(i=0;i<n-1;i++){
		if(s[i]=='1'){
			cout << x << " " << i+2 << endl;
			x = i+2;
		}else{
			cout << x << " " << i+2 << endl;
		}
	}
}
	
### Prompt

In Cpp, your task is to solve the following 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

### Response

```cpp
#include <iostream>
#include <string>

using namespace std;
int main(){
	int i,n;
	string s;
	cin >> s;
	n = s.size();
	if(s[0]=='0' || s[n-2]=='0' || s[n-1]=='1'){
		cout << -1 << endl;
		return 0;
	}
	for(i=0;i<n-1;i++){
		if(s[i]!=s[n-2-i]){
			cout << -1 << endl;
			return 0;
		}
	}
	int x = 1;
	for(i=0;i<n-1;i++){
		if(s[i]=='1'){
			cout << x << " " << i+2 << endl;
			x = i+2;
		}else{
			cout << x << " " << i+2 << endl;
		}
	}
}
	
```