You are given a code:

def main_solution(x):
    return func_13(func_20(x, 'utlrvq'), '-')

Can you predict the output of `main_solution("dva")` 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": "dva"}, "ref_output": "d-u-v-t-a-l-r-v-q", "ref_code": "def main_solution(x):\n    return func_13(func_20(x, 'utlrvq'), '-')", "funcname": "main_solution"}
rule