sub addone{
#        1         2         3         4         5         6
#23456789_123456789_123456789_123456789_123456789_123456789_123456789
($_,$s)=@_;y/A-Z/:-T/;$s=36*$s-48+ord for/./g;$s++;$t.=chr(($s%36)+48
#        8         9        10        11        12
#23456789_123456789_123456789_123456789_123456789_12
),$s=($s-$s%36)/36while$s>0;$t=~y/:-T/A-Z/;reverse$t
}