You are given a code:

def main_solution(x):
    return (func_13(x, '_') + func_19('chgnum', 1))

Can you predict the output of `main_solution("rmllqimawn")` 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": "rmllqimawn"}, "ref_output": "r_m_l_l_q_i_m_a_w_nhgnumc", "ref_code": "def main_solution(x):\n    return (func_13(x, '_') + func_19('chgnum', 1))", "funcname": "main_solution"}
rule