You are given a code:

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

Can you predict the output of `main_solution("wsyzosnk")` 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": "wsyzosnk"}, "ref_output": "w_s_y_z_o_s_n_k_a_l_r_v_w_m", "ref_code": "def main_solution(x):\n    return func_13((x + 'alrvwm'), '_')", "funcname": "main_solution"}
rule