#include <iostream>
#include <string>
using namespace std;

int main() {
	string S;
	cin >> S;
	int n=S.size();
	if(S[0]=='0' || S[n-1]=='1'){
		cout << -1 << endl;
		return 0;
	}
	for(int i=0; i<n-2-i; ++i){
		if(S[i]!=S[n-2-i]){
			cout << -1 << endl;
			return 0;
		}
	}
	int now=1;
	for(int i=2; i<=n; ++i){
		cout << now << ' ' << i << endl;
		if(S[i-2]=='1'){
			now=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 <iostream>
#include <string>
using namespace std;

int main() {
	string S;
	cin >> S;
	int n=S.size();
	if(S[0]=='0' || S[n-1]=='1'){
		cout << -1 << endl;
		return 0;
	}
	for(int i=0; i<n-2-i; ++i){
		if(S[i]!=S[n-2-i]){
			cout << -1 << endl;
			return 0;
		}
	}
	int now=1;
	for(int i=2; i<=n; ++i){
		cout << now << ' ' << i << endl;
		if(S[i-2]=='1'){
			now=i;
		}
	}
	return 0;
}
```