/=$/P
s/.$//
//D
H
s/^/--/
:
s/\(.\)\(.\)/=--\1---\2/g
T
s///257
T
x
:1
s/.\w*/&0&1&2&3&4&5&6&7&8&9/g
s/0//
/999/!b1
G
D