johngg@abouriou ~/perl/Monks $ perl -Mstrict -Mwarnings -E '
my @arr    = ( 3, 4, 71, 1, -598, -100203 );
say for (
   sort { $arr[ $a ] <=> $arr[ $b ] }
   grep { $arr[ $_ ] >= 0 }
   0 .. $#arr
   )[ 0 ];'
3