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

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
#define rep1(i,n) for(int i=1;i<=int(n);++i)

int main(void){
    string s;
    cin>>s;
    int n = s.size();
    s = "0" + s;
    if(s[1] == '0' || s[n-1] == '0' || s[n] == '1'){
        cout<<-1<<endl;
        return 0;
    }
    
    rep1(i,n/2){
        if(s[i] != s[n-i]){
            cout<<-1<<endl;
            return 0;
        }
    }

    int head = 1;
    rep1(i,n-1){
        cout<<head<<" "<<i+1<<endl;
        if(s[i] == '1') head = i+1;
    }
    return 0;
}