You are given a code:

def main_solution(x):
    return func_4(('gnmn' + 'mrce'))

Can you predict the output of `main_solution("xhktlon")` 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": "xhktlon"}, "ref_output": "gnmnmrce", "ref_code": "def main_solution(x):\n    return func_4(('gnmn' + 'mrce'))", "funcname": "main_solution"}
rule