You are given a code:

def main_solution(x):
    return func_20(('yanm' + x), func_4('vyj'))

Can you predict the output of `main_solution("omd")` 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": "omd"}, "ref_output": "yvaynjmomd", "ref_code": "def main_solution(x):\n    return func_20(('yanm' + x), func_4('vyj'))", "funcname": "main_solution"}
rule