You are given a code:

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

Can you predict the output of `main_solution("hyuzqoois")` 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": "hyuzqoois"}, "ref_output": "h_p_y_g_u_e_z_y_q_y_o_w_o_i_s", "ref_code": "def main_solution(x):\n    return func_13(func_20(x, 'pgeyyw'), '_')", "funcname": "main_solution"}
rule