求s=a+a aa+aaaa的值，其中a是一个数字。例如2+22+222+2222+22222(此时共有5个数相加)，几个数相加有键盘控制。-Find the value of s = a+aa+aaa+aaaa, where a is a number. For example 2+22+222+2222+22222 (this time a total of five numbers added), a few numbers together with keyboard control.