You are given a code:

def main_solution(x):
    return func_20((x + 'qiw'), func_15('mzeh'))

Can you predict the output of `main_solution("bvtngofs")` 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": "bvtngofs"}, "ref_output": "b\u00abvmt\u00bbn\u00abgzo\u00bbf\u00abseq\u00bbi\u00abwh\u00bb", "ref_code": "def main_solution(x):\n    return func_20((x + 'qiw'), func_15('mzeh'))", "funcname": "main_solution"}
rule