时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 1024 M，其他语言2048 M
Special Judge, 64bit IO Format: %lld
空间限制：C/C++/Rust/Pascal 1024 M，其他语言2048 M
Special Judge, 64bit IO Format: %lld
题目描述
Construct a string 
of length 
with the character set 
such that there are exactly 
square substrings.
A square substring is a string of the form
, where 
is any non-empty substring. For example, the string 
has two square substrings.
A square substring is a string of the form
输入描述:
The first line of input contains two integersand
.
输出描述:
If there is a solution, outputon the first line. On the second line, output
.
Otherwise, outputon a single line.
备注:
.