CF626A.Robot Sequence

Calvin the robot lies in an infinite rectangular grid. Calvin's source code contains a list of n commands, each either 'U', 'R', 'D', or 'L' — instructions to move a single square up, right, down, or left, respectively. How many ways can Calvin execute a non-empty contiguous substrings of commands and return to the same square he starts in? Two substrings are considered different if they have different starting or ending indices.

机器人卡尔文位于一个无限大的矩形网格中。卡尔文的源代码包含一个由 n 个命令组成的列表，每个命令为 'U'、'R'、'D' 或 'L' 中的一个，分别表示向上、向右、向下或向左移动一格。卡尔文执行多少种非空的连续子命令串后，能够回到其起始方格？若两个子串的起始索引或结束索引不同，则视为不同的子串。

The first line of the input contains a single positive integer, n (1 ≤ n ≤ 200) — the number of commands.

The next line contains n characters, each either 'U', 'R', 'D', or 'L' — Calvin's source code.

输入的第一行包含一个正整数 $n$（$1 \leq n \leq 200$）——命令的数量。

下一行包含 $n$ 个字符，每个字符为 'U'、'R'、'D' 或 'L' 中的一个——Calvin 的源代码。

Print a single integer — the number of contiguous substrings that Calvin can execute and return to his starting square.

输出一个整数——即 Calvin 可以执行并返回起始方格的连续子串的数量。

In the first case, the entire source code works, as well as the "RL" substring in the second and third characters.

Note that, in the third case, the substring "LR" appears three times, and is therefore counted three times to the total result.

在第一种情况下，整个源代码均有效，且第二和第三个字符组成的子串“RL”也有效。

注意，在第三种情况下，子串“LR”出现了三次，因此在最终结果中被计数三次。