%!PS

/ls {
    /base exch def
    /max 0 def
    base 1 sub -1 0 {
        /max max base mul def
        max add /max exch def
    } for
    /t max sqrt cvi def
    /digits (0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ) def
    {
        /s t t mul def
        /v true def
        /c base array def
        0 1 base 1 sub {
            c exch 0 put
        } for
        /dg base string def
        /i base def
        {
            s 0 le {
                exit
            } if
            /d s base mod def
            c d get 1 add c exch d exch put
            c d get 1 gt {
                /v false def
                exit
            } if
            /s s base idiv def
            /i i 1 sub def
            dg i digits d get put
        } loop
        v {
            exit
        } if
        /t t 1 sub def
    } loop
    /st 0 def
    /i 1 def
    dg {
        0 eq {
            /st i def
        } if
        /i i 1 add def
    } forall
    st 0 gt {
        dg st base st sub getinterval
    } {
      dg
    } ifelse
} bind def

2 ls (1) eq { (Pass) } { (FAIL) } ifelse
print ( ) print
4 ls (3201) eq { (Pass) } { (FAIL) } ifelse
print ( ) print
10 ls (9814072356) eq { (Pass) } { (FAIL) } ifelse
print ( ) print
12 ls (B8750A649321) eq { (Pass) } { (FAIL) } ifelse
=