You are given a code:

def main_solution(x):
    return func_20(('ftsu' + x), func_15('spn'))

Can you predict the output of `main_solution("cetsdbizyo")` 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": "cetsdbizyo"}, "ref_output": "f\u00abtss\u00bbu\u00abcpe\u00bbt\u00absnd\u00bbbizyo", "ref_code": "def main_solution(x):\n    return func_20(('ftsu' + x), func_15('spn'))", "funcname": "main_solution"}
rule