You are given a code:

def main_solution(x):
    return (('eiy' + 'xztdzb') + func_20('oyw', 'bzeb'))

Can you predict the output of `main_solution("mke")` 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": "mke"}, "ref_output": "eiyxztdzbobyzweb", "ref_code": "def main_solution(x):\n    return (('eiy' + 'xztdzb') + func_20('oyw', 'bzeb'))", "funcname": "main_solution"}
rule