You are given a code:

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

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