You are given a code:

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

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