You are given a code:

def main_solution(x):
    return (func_1('ffapmt', 4) + ('xzlliw' + 'kkfpbd'))

Can you predict the output of `main_solution("ybdi")` 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": "ybdi"}, "ref_output": "ffapmtffapmtffapmtffapmtxzlliwkkfpbd", "ref_code": "def main_solution(x):\n    return (func_1('ffapmt', 4) + ('xzlliw' + 'kkfpbd'))", "funcname": "main_solution"}
rule