You are given a code:

def main_solution(x):
    return (func_4('xldb') + func_5('dzc', 'rodg'))

Can you predict the output of `main_solution("tpfj")` 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": "tpfj"}, "ref_output": "xldbrodgdzc", "ref_code": "def main_solution(x):\n    return (func_4('xldb') + func_5('dzc', 'rodg'))", "funcname": "main_solution"}
rule