You are given a code:

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

Can you predict the output of `main_solution("betirsilb")` 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": "betirsilb"}, "ref_output": "b\u00abebt\u00bbi\u00abres\u00bbi\u00abltb\u00bbr\u00abhie\u00bbd\u00abr\u00bb\u00abs\u00bb\u00abi\u00bb\u00abl\u00bb\u00abb\u00bb", "ref_code": "def main_solution(x):\n    return func_20((x + 'rhed'), func_15(x))", "funcname": "main_solution"}
rule