use strict;
use warnings;

my($h, $w) = split ' ', <>;
my @map;
for(<>){
  push @map, [split ' ', $_];
}

my @queue = ();
my @vx = (0, 1, 0, -1);
my @vy = (1, 0, -1, 0);
my $count = 0;
my($pres, $next);
for my $y (0..$h-1){
  for my $x (0..$w-1){
    if($map[$y][$x] == 1){
      $map[$y][$x]++;
      push @queue, {x => $x, y => $y};
      while(@queue){
        $pres = shift @queue;
        for my $i (0..3){
          $next = {x => $pres->{x} + $vx[$i], y => $pres->{y} + $vy[$i]};
          if(-1 < $next->{x} and $next->{x} < $w and -1 < $next->{y} and $next->{y} < $h){
            if($map[$next->{y}][$next->{x}] == 1){
              $map[$next->{y}][$next->{x}]++;
              push @queue, {x => $next->{x}, y => $next->{y}};
            }
          }
        }
      }
      $count++;
    }
  }
}
print $count."\n";