reduce {
  %r = $1
  %i = 97
  while %i < 123 { 
    z %i +
    z 220-%i -
    inc %i
  }
  v - + 
  return %r
}
z v $2 $b($1- 1) $b($1) $b($1- 2)
v %r = $replace(%r,$+($3,$2,$4),$+($3,$1,$4),$+($1,$2,$4),$1 $+ $4)
b return $chr($calc($1))