如何删除行尾两个分隔符之间的字符串？

def remove_string_between_delimiters(input_string, delimiter):
    if delimiter not in input_string:
        return input_string
    
    parts = input_string.split(delimiter)
    if len(parts) < 3:
        return input_string
    
    output_string = delimiter.join(parts[:-2]) + delimiter
    return output_string

# 示例用法
input_string = "abc|def|ghi|jkl|mno|pqr|stu"
delimiter = "|"
output_string = remove_string_between_delimiters(input_string, delimiter)
print(output_string)