You are given a code:

def main_solution(x):
    return (func_19('tahe', 1) + ('pagby' + 'unh'))

Can you predict the output of `main_solution("umu")` 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": "umu"}, "ref_output": "ahetpagbyunh", "ref_code": "def main_solution(x):\n    return (func_19('tahe', 1) + ('pagby' + 'unh'))", "funcname": "main_solution"}
rule