Black plays and wins in 3 moves https://lichess.org/k99mCOHd/black
1... b2 2. Re1 Kb3 3. Rg1 a2#
The analysis board does checkmate in 5 moves
1... a2+ 2. Kb2 Rd2+ 3. Ka1 Ka3 4. Rb1 axb1=Q+ 5. Kxb1 Rd1#
Source:
This publication is in my collection "500 chess puzzles. Mate in 5. Advanced & Expert Level."