or download this
my %counts = (
"Adam" => { "201708" => 1, "201703" => 1, "201804" => 1, "
+201603" => 1, "201705" => 1, "201702" => 1, "201608" => 1, "201704" =
+> 1,},
...
my $minimal = max_by { $subhash->{$_} } keys %$subhash;
print "$key, $minimal\n";
}