#!/usr/bin/perl

use strict;
use warnings;

my @a1 = qw(a d g v 6 z h u t f e 0 n);
my @a2 = qw(h f t u);

my $last_index = (
  sort{ $a <=> $b }
    grep{ my $i = $a1[$_];
        grep{ $i eq $_ }@a2
        }(0..scalar(@a1)-1))[-1];
        
print $last_index;