please can you help me to solve this by java

You have developed an e-commerce website. Many people have created accounts on your website. You have the passwords of all the users. You want to know how many distinct passwords there are in total. The details of a password are as described below. - Each password is a string of characters from a to z (small letters). - Two passwords, for example, Pass1 and Pass2, are said to be the same if Pass 2 can be obtained by swapping the ith characte with the jth character in Pass1, where (i+j)%2=0. Note: Swapping can be done repeatedly