In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

Input: Consider Input: Boolean operations is a method of combining _ meshes together.

Output: two


Input: Consider Input: Autism is _ to four times more likely to affect boys than girls.

Output: three


Input: Consider Input: Monochorionic twins have _ times the risk of abnormality that dichorionic twins do.


Output: ten