WordPiece Score

Compute the WordPiece merge score of a candidate pair: the pair's frequency divided by the product of the frequencies of its two parts, ${\displaystyle \frac{\text{count}(ab)}{\text{count}(a)\cdot \text{count}(b)}}\backslash dfrac\{\backslash text\{count\}(ab)\}\{\backslash text\{count\}(a)\backslash cdot\backslash text\{count\}(b)\}$.

Implement solve(pair_count,left_count,right_count).

Returns. Return a float. The part frequencies must be positive.

Examples

Example 1

Input:

solve(2.0, 3.0, 1.0)

Output:

0.666667

Example 2

Input:

solve(5.0, 5.0, 5.0)

Output:

0.2