Minimum Adjacent Swaps Transformation

You are given two strings s and t of equal length. Your task is to compute the minimum number of adjacent swaps required to transform s into t. In each swap, you may only swap two consecutive characters in the string.

If the transformation is impossible, output \(-1\). It can be shown that the number of required swaps is unique when the transformation is possible.

Note: Two strings can be transformed into each other only if they are anagrams. In other words, if \(sorted(s) \neq sorted(t)\), then the answer is \(-1\).

Examples:

• For s = "abcd" and t = "dcba", the minimum swaps required is 6.
• For s = "ab" and t = "ba", the answer is 1.
• For s = "abcd" and t = "abce", the answer is -1 since a transformation is impossible.

inputFormat

The input consists of two lines:

1. The first line contains the string s.
2. The second line contains the string t.

Both strings will have the same length and contain only lowercase English letters.

outputFormat

Output a single integer, representing the minimum number of adjacent swaps required to transform s into t, or -1 if such a transformation is impossible.

## sample

abcd
dcba

6

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