You are given a code:

def main_solution(x):
    return func_20(func_13(x, '_'), func_15('wph'))

Can you predict the output of `main_solution("cdgxtspibq")` 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": "cdgxtspibq"}, "ref_output": "c\u00ab_wd\u00bb_\u00abgp_\u00bbx\u00ab_ht\u00bb_s_p_i_b_q", "ref_code": "def main_solution(x):\n    return func_20(func_13(x, '_'), func_15('wph'))", "funcname": "main_solution"}
rule