Mate in 3 · No. 448 · Harder

Two rooks, bishop and knight

White to play and mate in three.

Position

White
king on g5, rooks on a7 and f6, bishop on e4, knight on d6, pawns on a2, b3 and h3
Black
king on b6, rook on e7, pawns on a3, b4, b5 and e5