#/bin/bash

function 1337() {
  echo $@ | tr '[:upper:]' '[:lower:]' | \
  tr 'letaos' '137405' | \
  sed 's/and\ /\&\ /g'
}

opt="$@"
[ -n "$opt" ] && 1337 "$opt" && exit

while read stdin; do
  1337 "$stdin"
done