#include <iostream>
#include <string>

using namespace std;

int main(void) {
  string s;
  cin>>s;
  s="0"+s;

  if(s==string(s.rbegin(), s.rend()) && s[1]=='1') {
    int r=1;
    for(int i=2; i<s.size(); i++) {
      printf("%d %d\n", r, i);
      if(s[i-1]=='1') r=i;
    }
  } else {
    puts("-1");
  }
  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(void) {
  string s;
  cin>>s;
  s="0"+s;

  if(s==string(s.rbegin(), s.rend()) && s[1]=='1') {
    int r=1;
    for(int i=2; i<s.size(); i++) {
      printf("%d %d\n", r, i);
      if(s[i-1]=='1') r=i;
    }
  } else {
    puts("-1");
  }
  return 0;
}

```