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A14227. Min Cost String

编程题 普及/提高-

题目描述

Let's define the cost of a string $s$ as the number of index pairs $i$ and $j$ ( $1 \le i < j < |s|$ ) such that $s_i = s_j$ and $s_{i+1} = s_{j+1}$ .

You are given two positive integers $n$ and $k$ . Among all strings with length $n$ that contain only the first $k$ characters of the Latin alphabet, find a string with minimum possible cost. If there are multiple such strings with minimum cost — find any of them.

输入格式

The only line contains two integers $n$ and $k$ ( $1 \le n \le 2 \cdot 10^5; 1 \le k \le 26$ ).

输出格式

Print the string $s$ such that it consists of $n$ characters, each its character is one of the $k$ first Latin letters, and it has the minimum possible cost among all these strings. If there are multiple such strings — print any of them.

输入输出样例

输入 #1
9 4
输出 #1
aabacadbb
输入 #2
5 1
输出 #2
aaaaa
输入 #3
10 26
输出 #3
codeforces
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