#!/usr/bin/sed -nf 

# Skip comment lines
/^@.*$/ b

# Count empty lines. Excute this for all empty lines
/^$/ {

     # Exchange pattern and hold space
     x
     /^$/ s/^.*$/1/

     # Append hold space to pattern space
     G

     # copy pattern space to hold space
     h

     # /p --> print the new pattern space
     s/^/      /
     s/^ *\(......\)\n/\1  /

     # Exchange pattern and hold space
     x

     s/\n.*$//
     /^9*$/ s/^/0/
     s/.9*$/x&/


     # copy pattern space to hold space
     h

     s/^.*x//
     y/0123456789/1234567890/

     # Exchange pattern and hold space
     x

     s/x.*$//

     # Append hold space to pattern space
     G

     s/\n//

     # copy pattern space to hold space
     h

     # exit script
     b
}

# If the line is non-empty print out line number of last empty line
# end the contents of the non-empty line

# Append hold space to pattern space
G
# Exchange the two lines and create valid output
s/\(.*\)\n\(.*\)/\2: \1/
# In the case of the first line the number is not yet initialized
s/^:/1:/
# Print pattern space
p
b