Classify each of the following as either a letter or a number
1, a, o, 3, 9, 193, d, 23, f, d, p, 500
<START_INST>Classify each of the following as either a letter or a number<END_INST><START_CTX><END_CTX><START_A>1, a, o, 3, 9, 193, d, 23, f, d, p, 500<END_A>