We call them twin primes because, except for the case of 2 and 3, the least difference between two prime numbers is 2.

### Examples

- The numbers 11 and 13 are twin primes because they are two prime numbers with a difference of 2.
- Some other pairs of twin primes include: (5, 7), (17, 19), (41, 43), (197, 199), (641, 643).