Limits 2s, 1.0 GB

**Sanvi** is a very little and so much cute girl. She was playing with an array **A** of length **N**. While doing so, Sanvi discovers an interesting pattern with the pairing of two elements in that array. She defines a term ‘**Happy Pair**’ as pairing of two integer numbers, say **P** and **Q**, if bitwise XOR of these integers is a power of 2 i.e **( P XOR Q = 2^X )** , where X is an integer number. Now, she is challenging you with the following task.

This is a companion discussion topic for the original entry at https://toph.co/p/sanvi-and-happy-pairs