s/ / > /
/^\(.*\) > \1$/s/>/=/
h
:0
s/.\W\+./ /
t0
/. /b
/ ./b1
g
s/$/@9876543210/
/^\(.*\)\(.\).* \1\(.\).*@.*\2.*\3/b
:1
g
s/>/</
h
:
g