s/one/o1e/g
s/two/t2o/g
s/three/t3e/g
s/four/4/g
s/five/5e/g
s/six/6/g
s/seven/7n/g
s/eight/e8t/g
s/nine/n9e/g
s/[^0-9]//g
s/^(.).*(.)$/\1\2/g
s/^(.)$/\1\1/g