White plays and wins in 3 moves https://lichess.org/H6vdHx7t
- Kc6 Rf4 2. Rh8+ Rf8 3. Rxf8#
The analysis board does checkmate in 5 moves
- c6 Rd4 2. b7+ Kb8 3. Rh8+ Rd8 4. Rxd8+ Kc7 5. b8=Q#
Source:
This publication is in my collection "500 chess puzzles. Mate in 5. Advanced & Expert Level."