import sequtils,queues

proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int32 =
  while true:
    let k = getchar_unlocked()
    if k < '0': break
    result = 10.int32 * result + k.ord.int32 - '0'.ord.int32

type UnionFind[T] = object
  parent : seq[T]
  # rank : seq[int16]
proc root[T](self:var UnionFind[T],x:T): T =
  if self.parent[x] == x: return x
  self.parent[x] = self.root(self.parent[x])
  return self.parent[x]
proc initUnionFind[T](size:int) : UnionFind[T] =
  result.parent = newSeqUninitialized[T](size)
  # result.rank = newSeq[int16](size)
  for i in 0.int32..<size.int32: result.parent[i] = i
proc same[T](self:var UnionFind[T],x,y:T) : bool = self.root(x) == self.root(y)
proc unite[T](self:var UnionFind[T],sx,sy:T) : bool {.discardable.} =
  let rx = self.root(sx)
  let ry = self.root(sy)
  if rx == ry : return false
  self.parent[rx] = ry
  # if self.rank[rx] < self.rank[ry] : self.parent[rx] = ry
  # else:
  #   self.parent[ry] = rx
  #   if self.rank[rx] == self.rank[ry]: self.rank[rx] += 1
  return true


let h = scan()
let w = scan()
var uf = initUnionFind[int32](h * w + 1)
var ans = w * h
var i = 1.int32
for y in 0..<h:
  for x in 0..<w:
    if getchar_unlocked() == '1':
      if x > 0 and uf.parent[i-1] != 0:
        if uf.unite(i,i-1): ans -= 1
      if y > 0 and uf.parent[i-w] != 0:
        if uf.unite(i,i-w): ans -= 1
    else:
      uf.parent[i] = 0
      ans -= 1
    discard getchar_unlocked()
    i += 1
echo ans