Write a sed script that will:

a$.$ Remove the first number from a line, if it begins with a number

i$.$ For these lines, surround the entire line in $...$ tags

b$.$ Trim any repeat sequences of tabs and$/$or spaces down to a single space

c$.$ Replace all sequences of digits that reside immediately prior to a

hyphen with a single $$x$.$

Example input:

$25323$xr output freq $150\mathrm{.}32$

$8892$vfr outbound N$2137$ cs $12-01-1990$

ifr inbound N$9983$ heavy

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