You are given a code:

def main_solution(x):
    return (('bus' + 'xob') + func_15('jvo'))

Can you predict the output of `main_solution("pkdakpbfu")` 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": "pkdakpbfu"}, "ref_output": "busxob\u00abj\u00bb\u00abv\u00bb\u00abo\u00bb", "ref_code": "def main_solution(x):\n    return (('bus' + 'xob') + func_15('jvo'))", "funcname": "main_solution"}
rule