No. 29
4+2. Mate in 1 (b) Qa1->h8, Kc8->a8
5+2. Rectract 1 move, and #3.
13+5. Mate in 3
15+9. Mate in 1
7+8. Add a black rook so black doesn't lose.
7+2/5+3/4+4/2+3. 33 Upper left and upper right corner: Mate in 2. 34 Lower left and lower right corner: Helpmate in 2.
5+1. Mate in 2
3+4. Retract one move, and =1
3+8. h#2