#include<bits/stdc++.h>
using namespace std;

int n;
char s[100005];

int main() {
	scanf(" %s",s+1);
	n = strlen(s+1);
	if(s[1] == '0' || s[n] == '1') return !printf("-1");
	for(int i = 1; i <= n-1; i++) {
		if(s[i] != s[n-i]) return !printf("-1");
	}
	for(int x = 1, y = 1; x <= n; x++) {
		if(s[x] == '1' || x == n) {
			while(y<x) {
				printf("%d %d\n",y,x);
				y++;
			}
		}
	}
}
### 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<bits/stdc++.h>
using namespace std;

int n;
char s[100005];

int main() {
	scanf(" %s",s+1);
	n = strlen(s+1);
	if(s[1] == '0' || s[n] == '1') return !printf("-1");
	for(int i = 1; i <= n-1; i++) {
		if(s[i] != s[n-i]) return !printf("-1");
	}
	for(int x = 1, y = 1; x <= n; x++) {
		if(s[x] == '1' || x == n) {
			while(y<x) {
				printf("%d %d\n",y,x);
				y++;
			}
		}
	}
}
```