IOAI26: train=4000 (40% noise) | valid=500 (clean, 25% stratified from old valid) | test=3500 (label=-1: 75% of old valid + entire old test)

IOAI26: train=4000 (40% noise) | valid=500 (clean, stratified 25%) | test=1500 (labels hidden, stratified 75%)