若函数$f\left(x\right)=x^2-1\left(x\le -1\right)$，则$f^{-1}\left(4\right)$的值（    ）

    Long long ago, there ____ a king. He ____ new clothes very much. There ____ two ____.  They can make magic clothes. ____ people can see it. But foolish people can't. The king ____ through the city with new clothes. A lot of people looked at him and ____. A little boy ____ at the king and ____ "Ha! Ha! The king isn't ____ clothes!"

一个数除以15，商和余数都是14，这个数是____。