poppy:~/fondue/aoc/twenty(uio)$ ./five.py|sort -n|awk '{print $1 - NR, $1}'|less
poppy:~/fondue/aoc/twenty(uio)$ second<<<539

poppy:~/fondue/aoc/twenty(uio)$ ./five.awk input5 |sort -n|awk '$1!=(a+1) {us=a+1} 1 {a=$1} END {print $1; print us}'

poppy:~/fondue/aoc/twenty(uio)$ bc < <(echo 'ibase=2'; tr FLBR 0011 <input5) |sort -n |awk '$1!=a+1 {us=a+1} {a=$1} END {print $1; print us}'

poppy:~/fondue/aoc/twenty(uio)$ bc< <(echo 'ibase=2';tr FLBR 0011 <input5)|sort -n|awk '$1!=a+1{s=a+1}{a=$1}END{print$1"\n"s}'