import sequtils,queues

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

type UnionFind = object
  parent : seq[int32]
  rank : seq[int32]
proc root(self:var UnionFind,x:int32): int32 =
  if self.parent[x] == x: return x
  self.parent[x] = self.root(self.parent[x])
  return self.parent[x]
proc initUnionFind(size:int32) : UnionFind =
  result.parent = newSeqUninitialized[int32](size)
  result.rank = newSeq[int32](size)
  for i in 0.int32..<size.int32: result.parent[i] = i
proc same(self:var UnionFind,x,y:int32) : bool = self.root(x) == self.root(y)
proc unite(self:var UnionFind,x,y:int32)  =
  let rx = self.root(x)
  let ry = self.root(y)
  if rx == ry : return
  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


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

# let h = scan()
# let w = scan()
# var isWater : array[3001,array[3001,bool]]
# for y in 0..<h:
#   for x in 0..<w:
#     isWater[x][y] = getchar_unlocked() == '1'
#     discard getchar_unlocked()
# const dx = [1.int3232,-1.int3232,0.int3232,0.int3232]
# const dy = [0.int3232,0.int3232,1.int3232,-1.int3232]
# proc check(sx,sy:int3232)  =
#   var X = initQueue[int3232]()
#   var Y = initQueue[int3232]()
#   X.enqueue(sx)
#   Y.enqueue(sy)
#   isWater[sx][sy] = false
#   while X.len() > 0:
#     let x = X.dequeue()
#     let y = Y.dequeue()
#     template regist(nx,ny:int32) =
#       if isWater[nx][ny] :
#         X.enqueue(nx)
#         Y.enqueue(ny)
#         isWater[nx][ny] = false
#     if x > 0: regist(x-1,y)
#     if y > 0: regist(x,y-1)
#     if x < w-1: regist(x+1,y)
#     if y < h-1: regist(x,y+1)
# var ans = 0
# for x in 0.int3232..<w.int3232:
#   for y in 0.int3232..<h.int3232:
#     if not isWater[x][y]: continue
#     check(x,y)
#     ans += 1
# echo ans