s/^/10#2/
:
s/+/<<10123456789abcdefghijklmnopqrstuvww>/
s/\(.\)<.*\1\(.\).*>/\2/
s/\(.\)\(\S*#\1\)/+0\2/
t
h
s/#.//gp
/v/d
g
s/#/+#/g
s/#.$/& 10&+/
b