Patriotic Ribbon

Limits: 2 sec., 256 MiB

This statement was translated automatically from Ukrainian.

Petrik has a ribbon divided into \(n\) equal parts, where each part is painted in one of two colors — blue or yellow. Petrik considers the ribbon to be patriotic if no two adjacent parts are painted in the same color.

In one hour, Petrik can choose any part and repaint it to the other color (from blue to yellow or vice versa). Help Petrik determine the minimum number of hours required to make the ribbon patriotic.

Input

The single line contains a string \(s\) consisting of the characters B and Y.

The character B represents a blue part, and Y represents a yellow part.

Output

In a single line, print a single integer — the minimum number of hours.

Constraints

\(1 \le |s| \le 10^5\), where \(|s|\) is the number of characters in the string \(s\).

Samples

Input (stdin) сopy	Output (stdout) сopy
BYB	0

Input (stdin) сopy	Output (stdout) сopy
YYBBB	2

Notes

In the first example, Petrik doesn’t need to change anything — the given ribbon is already patriotic.

In the second example, Petrik can change the first and fourth parts to form the ribbon BYBYB.