You are given a code:

def main_solution(x):
    return (func_13(x, '_') + func_15('hypnaq'))

Can you predict the output of `main_solution("fcgaro")` 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": "fcgaro"}, "ref_output": "f_c_g_a_r_o\u00abh\u00bb\u00aby\u00bb\u00abp\u00bb\u00abn\u00bb\u00aba\u00bb\u00abq\u00bb", "ref_code": "def main_solution(x):\n    return (func_13(x, '_') + func_15('hypnaq'))", "funcname": "main_solution"}
rule