Calculate total coffees produced based on work/break schedule with fatigue rules.

Rules:

• w = work block (produces 5 coffees normally)
• b = break block (produces 0 coffees, resets fatigue)
• After 4 consecutive work blocks, fatigue sets in (0 coffees until break)

Examples

Example 1

Input:  "wwww"
Output: 15

5 + 5 + 5 + 0 (fatigue after 4th consecutive work)

Example 2

Input:  "wwbw"
Output: 15

5 + 5 + 0 + 5 (break resets fatigue)

Constraints

• Track consecutive work blocks
• Breaks reset fatigue counter