my $cnr = 2;
for my $xda ( shuffle 0 .. $total ) {
    if ( defined $aob[$xda][ $y - 1 ] ) {
        $aob[$x][$y] = $z + $aob[$xda][ $y - 1 ];
        last if --$cnr == 0;
   }
}

##</code><code>##

for my $xda ( shuffle 0 .. $total ) {
    if ( defined $aob[$xda][ $y - 1 ] ) {
        $aob[$x][$y] = $z + $aob[$xda][ $y - 1 ];
        last;
   }
}