You are given a code:

def main_solution(x):
    return func_4(func_5('neypwh', 'key'))

Can you predict the output of `main_solution("krs")` 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": "krs"}, "ref_output": "keyneypwh", "ref_code": "def main_solution(x):\n    return func_4(func_5('neypwh', 'key'))", "funcname": "main_solution"}
rule