You are given a code:

def main_solution(x):
    return func_13(func_1('uugvv', 2), '_')

Can you predict the output of `main_solution("gokc")` 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": "gokc"}, "ref_output": "u_u_g_v_v_u_u_g_v_v", "ref_code": "def main_solution(x):\n    return func_13(func_1('uugvv', 2), '_')", "funcname": "main_solution"}
rule