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>
const int MAXN=100005;

char s[MAXN];
int n;

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