$/+=<>;$_=<>;s/\./	/;$e="(.{$/})?";($a,$b)=(v9,A..Z,a..g)[$i,$i+1],s/\.$e	|	$e\./	$1$2	/s||s/$a$e#/$a$1$b/s|s/#$e$a/$b$1$a/s||$i++until/\w$e\.|\.$e\w/s;print$i+1