Even if the problem name is "P", "Q", "R", ..., it looks like standings json has "A", "B", "C", ... for problem ID, because of https://github.com/icpcsec/livesite/commit/156becdbd2b52c90aa2fa96c25922b83e4573278
Even if the problem name is "P", "Q", "R", ..., it looks like standings json has "A", "B", "C", ... for problem ID, because of 156becd