This is an easy problem. It is my first so feel free to comment.
(;AB[ak]AB[ck]AB[bk]AB[dj]AB[di]AB[dh]AB[ch]AW[dk]AW[cj]AW[ci]AW[bj]AW[aj]AW[bh]AW[cg]AW[dg]AW[ej]AW[fi]AW[fh]AB[cl]AB[cm]AW[em]C[Black to do his best]AP[goproblems]
(;B[eh];W[eg]C[Your stones die : (])
(;B[ei];W[eh]C[: (])
(;B[bg];W[ei]C[You lose your stones : (])
(;B[bi];W[ai]
(;B[ah];W[ag]C[You can not save your own stones in time])
(;B[bg];W[ei]C[You lose your stones : (])
(;B[eg];W[eh]C[: (]))
(;B[eg];W[eh]C[: (])
(;B[ah];W[ei]C[You lose your stones : (])
(;B[ai];W[bi];B[bg];W[ah];B[ag]C[];W[eh];B[ai]C[<(^_^)>RIGHT])
(;B[dl];W[bg]C[White saved his stones])
(;B[ek];W[bg]C[White saves his stones]))