You are given a code:

def main_solution(x):
    return func_20(func_13(x, '_'), ('uamivr' + 'gpvdmn'))

Can you predict the output of `main_solution("bsvvts")` 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": "bsvvts"}, "ref_output": "bu_asm_ivv_rvg_ptv_dsmn", "ref_code": "def main_solution(x):\n    return func_20(func_13(x, '_'), ('uamivr' + 'gpvdmn'))", "funcname": "main_solution"}
rule