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<cstdio>
#include<cstring>
#include<cstdlib>
#include<iostream>
using namespace std;

char s[100010];
struct edge{
	int x,y;
}p[100010];
int len=0;
int tot=1;
int n;

int main(){
	scanf("%s",s+1);
	n=strlen(s+1);
	if(s[1]!='1'){
		printf("-1");
		return 0;
	}
	if(s[n]=='1'){
		printf("-1");
		return 0;
	}
	for(int i=1;i<=n-1;i++) if(s[i]!=s[n-i]){
		printf("-1");
		return 0;
	}
	printf("%d %d\n",1,2);
	int now=2;
	for(int i=2;i<=n-1;i++){
		printf("%d %d\n",now,i+1);
		if(s[i]=='1') now=i+1;
	}
}