This still has some problems
If the last two lines of the input are a heading, they get eaten
Why?
/^\(.\)1円1円*$/ { x;
y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/;
x; d;
}
This uppercases the hold space
but d skips the print and starts prcessing the next line of input
$ { p;x; }
So the special last-line behavior is skipped
I tried hard to fix this, but I'm not clever enough