Problem Description

Suppose you have a wooden board of length $5$, initially uncolored. You wish to paint its $5$ units of length in red, green, blue, green, and red, respectively, represented by a string of length $5$: $\texttt{RGBGR}$.

Each time, you can paint a continuous segment of the board with a given color, with subsequent colors overwriting previous ones. For example, first paint the board as $\texttt{RRRRR}$, then as $\texttt{RGGGR}$, and finally as $\texttt{RGBGR}$, achieving the target.

Use the fewest number of painting operations to reach the target.

Input Format

The input consists of a single line containing a string of length $n$, which is the target coloring. Each character in the string is an uppercase letter, where different letters represent different colors, and the same letters represent the same color.

Output Format

The output consists of a single number, which is the minimum number of painting operations required.

Sample Input and Output

Sample Input #1

AAAAA

Sample Output #1

1

Sample Input #2

RGBGR

Sample Output #2

3

Notes

$40\%$ of the test cases satisfy $1 \le n \le 10$.

$100\%$ of the test cases satisfy $1 \le n \le 50$.

见题面 Input 部分

见题面 Output 部分