#! perl
use strict;
use warnings;

while (<DATA>)
{
    print "$1.$2\n" if m{ ^ \s* Pin: \s* ([^.]*?) \. (\S*) (?: \s+ out)? $ }x;
}

__DATA__
  Pin:  U343.IN1  in
  Pin:  U713.INP  out
  Pin:  U714.QN