It's my first problem, let me know the possible improvements!
I was playing this game and... made the black mistake ;(
(;AB[mb]AB[lc]AB[nc]AB[pe]AB[ld]AB[kd]AB[md]AB[ni]AB[nj]AB[mi]AB[ph]AB[qg]AB[rh]AW[lb]AW[kc]AW[jc]AW[ib]AW[jd]AW[je]AW[ke]AW[lf]AW[nd]AW[mh]AW[li]AW[lj]AB[ne]AW[od]AW[la]AB[mg]LB[mg:A]AW[oc]AW[pb]AB[rb]AW[jh]AB[pd]AW[jg]AB[ma]C[Black thinks his strong enough... after his mistake, White to find a way to save some stones (Black does not have KO threat)]AW[jj]AB[qa]AB[nf]AB[oe]AB[qc]AB[nh]AW[jb]AP[goproblems]
(;W[me];B[ob]C[]
(;W[oa];B[pc])
(;W[pc];B[oa];W[pa];B[qb])
(;W[le];B[pc]))
(;W[nb]
(;B[mc]C[CHOICE]
(;W[me]
(;B[na]C[CHOICE]
(;W[le];B[ob]
(;W[pa];B[pc])
(;W[oa];B[pc])
(;W[pc];B[pa]))
(;W[ob];B[pa];W[oa]C[niceRIGHT])
(;W[oa];B[ob]
(;W[le];B[pc])
(;W[pc];B[pa])))
(;B[oa]C[CHOICE]
(;W[na];B[ob])
(;W[ob];B[pa];W[na]C[goodRIGHT];B[qb];W[le]C[RIGHT])
(;W[pa];B[pc];W[ob];B[qb];W[na];B[oa]C[not good])
(;W[le];B[na];W[pa];B[ob]
(;W[nb]C[RIGHT])
(;W[pc];B[qb])))
(;B[ob];W[oa];B[pc];W[ob];B[qb];W[le]C[niceRIGHT]))
(;W[na];B[me])
(;W[pc];B[me])
(;W[ob];B[me]C[no chance anymore]))
(;B[na]C[CHOICE]
(;W[mc]
(;B[oa]
(;W[me];B[nc]
(;W[ob]
(;B[pa]
(;W[le];B[mc])
(;W[mc]C[KO];B[lh];W[le]C[RIGHT]))
(;B[pc]
(;W[mc]C[KO];B[lh];W[le];B[pa];W[kh]C[RIGHT])
(;W[pa];B[qb])))
(;W[le];B[mc]
(;W[ob];B[pa])
(;W[pa];B[ob]
(;W[nb]C[RIGHT])
(;W[pc];B[qb]))))
(;W[pa]
(;B[nc];W[ob]
(;B[mc];W[me];B[qb];W[le]C[RIGHT])
(;B[me]C[CHOICE];W[mc]C[goodRIGHT]))
(;B[me];W[ob]C[RIGHT])))
(;B[me];W[oa]C[RIGHT]))
(;W[me];B[ob]
(;W[pc];B[pa])
(;W[le];B[pc]))
(;W[ob]
(;B[mc]C[CHOICE];W[me];B[pa];W[oa]C[goodRIGHT])
(;B[me]C[CHOICE];W[mc];B[lh];W[oa]C[RIGHT]))
(;W[oa];B[ob]
(;W[pc];B[pa])
(;W[me];B[pc])
(;W[pa];B[pc])
(;W[lh];B[pc])))
(;B[me];W[mc]
(;B[lh];W[na]C[RIGHT])
(;B[kb];W[na]C[RIGHT]))
(;B[pc]
(;W[ob]
(;B[me];W[mc];B[lh];W[na]C[RIGHT])
(;B[mc];W[me];B[pa]
(;W[na]C[RIGHT])
(;W[oa];B[qb])))
(;W[mc]C[];B[ob]
(;W[na];B[nc])
(;W[oa];B[nc];W[ob];B[me];W[mc];B[lh];W[na]C[RIGHT])))
(;B[ob]C[CHOICE]
(;W[oa];B[pc]
(;W[ob]
(;B[me]C[CHOICE];W[mc];B[lh];W[na]C[RIGHT])
(;B[mc];W[me];B[qb];W[le]C[RIGHT]))
(;W[mc];B[me];W[na]C[RIGHT]))
(;W[mc]
(;B[pc]C[CHOICE]
(;W[oa];B[nc];W[ob]
(;B[mc];W[me];B[qb];W[le]C[RIGHT])
(;B[me];W[mc];B[qb];W[na]C[RIGHT]))
(;W[na];B[nc]C[you miss too many stones...]))
(;B[oa]C[CHOICE]
(;W[na]
(;B[pc]
(;W[pa];B[me]C[RIGHT])
(;W[nc]
(;B[pa];W[me]C[well done, but a White stone is missingRIGHT])
(;B[me];W[pa]C[RIGHT])))
(;B[pa]
(;W[pc];B[qb];W[nc];B[me]C[RIGHT])
(;W[me];B[pc];W[nc]C[well done. But a White stone is missingRIGHT])))
(;W[pa];B[nc]
(;W[pc];B[qb])
(;W[me];B[pc])
(;W[na]
(;B[mc];W[me];B[ob]
(;W[oa];B[pc];W[ob];B[qb])
(;W[le]C[RIGHT]))
(;B[me];W[mc]C[RIGHT]))))))
(;B[oa]C[CHOICE]
(;W[ob];B[pa]
(;W[na];B[me];W[mc]C[goodRIGHT])
(;W[me]
(;B[na];W[mc]
(;B[lh];W[le]C[RIGHT])
(;B[qb]
(;W[le]C[RIGHT])
(;W[lh];B[nc];W[le];B[pc])))
(;B[mc];W[na];B[qb];W[le]C[RIGHT]))
(;W[mc];B[na];W[me]
(;B[nc];W[le];B[qb];W[mc]C[RIGHT])
(;B[qb]
(;W[lh];B[nc];W[le];B[pc])
(;W[le]C[RIGHT]))
(;B[lh];W[le]C[RIGHT])))
(;W[na];B[ob]C[two eyes!..])
(;W[pa];B[pc]
(;W[ob];B[mc];W[me];B[qb];W[na];B[oa])
(;W[mc]
(;B[me];W[na];B[qb];W[ob]C[good but without senteRIGHT])
(;B[ob];W[na]C[RIGHT];B[me]C[RIGHT])))
(;W[mc]C[]
(;B[na]C[CHOICE]
(;W[pa];B[nc]
(;W[ob]
(;B[me];W[mc]C[RIGHT])
(;B[mc];W[me];B[qb];W[le]C[RIGHT]))
(;W[me];B[ob];W[le];B[pc]))
(;W[me];B[nc]
(;W[ob];B[pa];W[mc];B[mf];W[le]C[RIGHT])
(;W[pa];B[ob]
(;W[le];B[pc])
(;W[pc]C[bad... no need to Black to answer];B[qb]))
(;W[le]C[RIGHT]
(;B[mc]
(;W[pa];B[ob];W[nb]C[RIGHT])
(;W[ob];B[pa]))
(;B[ob]
(;W[pa];B[pc])
(;W[mc];B[pc];W[md]C[fine but a stone is missing]))))
(;W[ob];B[pa];W[me];B[nc];W[le];B[mc]C[you missed but now have a nice ko threat]))
(;B[ob];W[na];B[me];W[pa]C[RIGHT]))
(;W[me];B[na]
(;W[pa];B[ob]
(;W[pc];B[qb])
(;W[le];B[pc]))
(;W[ob];B[pa];W[mc];B[lh];W[le]C[RIGHT])
(;W[mc];B[pa];W[le];B[ob]
(;W[nc];B[pc]C[miss one white stone (but you get four Black stones :))RIGHT])
(;W[pc];B[nc];W[md];B[qb]
(;W[nb];B[lh]C[RIGHT])
(;W[lh]C[RIGHT]))))))
(;W[lh];B[me]C[not this stone !])
(;W[mf];B[me])
(;W[ob];B[me];W[nb];B[mc]C[not good...])
(;W[na];B[me];W[nb];B[mc])
(;W[pc])
(;W[lg];B[me]C[oups...]))