Load your document as one big string and search that,

open my $fh, '<', 'target.txt'; ## open your file
my $file;
{
  local $/ = undef;     ## disable the line seperator variable.
  $file = <$fh>;        ## load your file to a string.
  close $fh;            ## close your file
}

my $phrase = qr{        ## begin phrase 
  Leonardo  \s+         ## needed to avoid weird whitespace issues
  da        \s+         ## needed to avoid weird whitespace issues 
  Vinci }gxms;          ## match all occurences of our phrase

# Returns an array with all the matches
my @matches = $file =~ $phrase;

# Returns a count of how many matches you had for your string
print "Found " . @matches . " matches\n";
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