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>
#define fail return puts("-1"), 0

const int N = 1e5 + 5;

char s[N];

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