#include<bits/stdc++.h>
#define ll long long
#define N 200005
using namespace std;
int n;
char s[N];
void add(int x,int y){
	printf("%d %d\n",x,y);
}
int main(){
	scanf("%s",s+1);
	n=strlen(s+1);
	if (s[1]=='0'){
		puts("-1");
		return 0;
	}
	if (s[n]=='1'){
		puts("-1");
		return 0;
	}
	for (int i=1;i<=n-1;i++)
	if (s[i]!=s[n-i]){
		puts("-1");
		return 0;
	}
	int last=1; s[n]='1';
	for (int i=2;i<=n;i++){
		if (s[i]=='0') continue;
		add(i,last);
		for (int j=last+1;j<i;j++) add(i,j);
		last=i;
	}
}
### 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<bits/stdc++.h>
#define ll long long
#define N 200005
using namespace std;
int n;
char s[N];
void add(int x,int y){
	printf("%d %d\n",x,y);
}
int main(){
	scanf("%s",s+1);
	n=strlen(s+1);
	if (s[1]=='0'){
		puts("-1");
		return 0;
	}
	if (s[n]=='1'){
		puts("-1");
		return 0;
	}
	for (int i=1;i<=n-1;i++)
	if (s[i]!=s[n-i]){
		puts("-1");
		return 0;
	}
	int last=1; s[n]='1';
	for (int i=2;i<=n;i++){
		if (s[i]=='0') continue;
		add(i,last);
		for (int j=last+1;j<i;j++) add(i,j);
		last=i;
	}
}
```