(;AW[ba]AW[bc]AW[cc]AW[cd]AW[dd]AW[ed]AW[ec]AW[eb]AW[ea]AB[fa]AB[fb]AB[fc]AB[fd]AB[fe]AB[ee]AB[de]AB[be]AB[ce]AB[bd]AB[ac]AW[cb]C[Black can't kill White but has the best result.FORCE]AP[goproblems]
(;B[aa]C[FORCE];W[ab]C[FORCE];B[ad])
(;B[ab]C[FORCE];W[bb]C[RIGHT])
(;B[bb]C[FORCE];W[ab]C[FORCE];B[ad]))