Get Max Deletions

Unit moves UDLR are executed on an infinite plane with no obstacles. Delete any instructions, not necessarily contiguous, while keeping the final coordinates unchanged; find the maximum number of instructions that can be deleted.

输入格式

One line with an instruction string of length 1..100000, containing only U, D, L, and R.

输出格式

Output a single integer answer.

样例 1

输入：

UDLR

输出：

4

样例 2

输入：

UUURD

输出：

2

样例 3

输入：

L

输出：

0

样例说明

The outputs of the three public examples are, in order: 4; 2; 0. These answers have been checked by independent enumeration or direct simulation.