You can read in the task description: "...The other letters don't have power and are only victims."

letter 'a' was not specified in the intructions as a left side or right side letter but was still included in at least one test case, I suggest adding that 'letters not listed here may also be in the test cases' or remove the letter 'a' from the test cases [Python]

use a dictionary, assign left side as positive values and right side as negative values :v