You are given a code:

def main_solution(x):
    return (func_3('ynntu') + func_13(x, '_'))

Can you predict the output of `main_solution("amjfknaovs")` 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": "amjfknaovs"}, "ref_output": "nntuya_m_j_f_k_n_a_o_v_s", "ref_code": "def main_solution(x):\n    return (func_3('ynntu') + func_13(x, '_'))", "funcname": "main_solution"}
rule