You are given a code:

def main_solution(x):
    return (func_13(x, '|') + func_4('rks'))

Can you predict the output of `main_solution("rpdzgap")` 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": "rpdzgap"}, "ref_output": "r|p|d|z|g|a|prks", "ref_code": "def main_solution(x):\n    return (func_13(x, '|') + func_4('rks'))", "funcname": "main_solution"}
rule