You are given a code:

def main_solution(x):
    return func_9(func_13('ihruu', '_'))

Can you predict the output of `main_solution("aymefzr")` 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": "aymefzr"}, "ref_output": "i_h_r_u_uu_u_r_h_i", "ref_code": "def main_solution(x):\n    return func_9(func_13('ihruu', '_'))", "funcname": "main_solution"}
rule