string length comparer this program has to take two strings and compare their length, then tell you which one is longer (string-a or string-b) and by how much

rules:


no using .length or other built-in length checking methods (duh!)
no using addition or subtraction, this includes improvised addition/subtraction, in case you find some sort of weird improvisation.
no &gt; / &lt; (greater then/less then) inside if / if-else statements (you can use them in loops though), this obviously includes &gt;= etc. and no cheating (bool = a &gt; b;if(bool))
emphasis is on short rather then efficient code
oh yeah almost forgot... good luck!
SED, 45 (43 + 2 for the -n flag)

s/./a/g
h
n
s/./b/g
G
:a
s/b\(.*\)a/\1/
ta


Expects input as two separate lines, outputs the difference in unary, using "a" or "b" to indicate the longer string. run with sed -n.