You are given a code:

def main_solution(x):
    return func_20(func_20('ensa', 'oct'), func_15(x))

Can you predict the output of `main_solution("sltefby")` 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": "sltefby"}, "ref_output": "e\u00abosn\u00bbc\u00abslt\u00bba\u00abt\u00bb\u00abe\u00bb\u00abf\u00bb\u00abb\u00bb\u00aby\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_20('ensa', 'oct'), func_15(x))", "funcname": "main_solution"}
rule