You are given a code:

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

Can you predict the output of `main_solution("zuawl")` 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": "zuawl"}, "ref_output": "\u00ab_h_\u00bb_\u00ab_l_\u00bb_\u00ab_w_\u00bb_\u00ab_i_\u00bb_\u00ab_n_\u00bb", "ref_code": "def main_solution(x):\n    return func_13(func_15('hlwin'), '_')", "funcname": "main_solution"}
rule