You are given a code:

def main_solution(x):
    return func_20(func_15('eolmas'), (x + 'gyfrzb'))

Can you predict the output of `main_solution("qeqrtbaxbk")` without writing any code? Please reason and put your final answer in the following json format: {"output": <your output>}, where <your output> should be the final string.
user
{"ref_input": {"x": "qeqrtbaxbk"}, "ref_output": "\u00abqee\u00bbq\u00abrot\u00bbb\u00abalx\u00bbb\u00abkmg\u00bby\u00abfar\u00bbz\u00abbs\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15('eolmas'), (x + 'gyfrzb'))", "funcname": "main_solution"}
rule