1step,rule,n_before,n_after,n_removed,rationale21,"line parses into 5 well-formed fields (S+5-digit id; known municipality; ISO date; integer price, plain or quoted with comma thousands separators; positive numeric area)",1200,1164,36,corrupted/garbled lines cannot be read unambiguously; not reconstructed (TASK rule)32,sale_id unique among parsed records,1164,1164,0,duplicate ids would make record identity ambiguous4