You are given a code:

def main_solution(x):
    return func_20(func_4(x), func_15('cspd'))

Can you predict the output of `main_solution("iaecfimdv")` 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": "iaecfimdv"}, "ref_output": "i\u00abace\u00bbc\u00abfsi\u00bbm\u00abdpv\u00bb\u00abd\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_4(x), func_15('cspd'))", "funcname": "main_solution"}
rule