determining the number that was attached to each letteras in the case of , say , a d-8 was , in and of itself , a painstaking process of observation and speculation , as there was no way to concretely designate each prisoner an appropriate number without , first , knowing about his past and more importantly , about the circumstances that led up to his very existence , which wasto be surea daunting task to take on for any man who had been relegated to silence for as long as bunnu .