You are given a code:

def main_solution(x):
    return func_20(func_15('nqrk'), func_1(x, 3))

Can you predict the output of `main_solution("tbofpk")` 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": "tbofpk"}, "ref_output": "\u00abtnb\u00bbo\u00abfqp\u00bbk\u00abtrb\u00bbo\u00abfkp\u00bbktbofpk", "ref_code": "def main_solution(x):\n    return func_20(func_15('nqrk'), func_1(x, 3))", "funcname": "main_solution"}
rule