#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++) {
            cout << r << ' ' << i << endl;
            if(s[i-1] == '1') r = i;
        }
    } else {
        cout << -1 << endl;
    }
    return 0;
}

### Prompt

Create a solution in Cpp for 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(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++) {
            cout << r << ' ' << i << endl;
            if(s[i-1] == '1') r = i;
        }
    } else {
        cout << -1 << endl;
    }
    return 0;
}

```