Go: // AOJ 1160: How Many Islands? http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160

package main

import (
	"bufio"
	"container/list"
	"fmt"
	"os"
	"strconv"
)

var SEA = 0
var LAND = 1

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

func discoverIslands(M, V [][]int, H, W int) int {
	// 島を探す
	queue := list.New()
	islands := 0
	for i := 1; i <= H; i++ {
		for j := 1; j <= W; j++ {
			// 訪問済みの土地ならスキップ
			if V[i][j] == 1 {
				continue
			}

			// 訪問中の土地が海なら訪問済みにしてスキップ
			if M[i][j] == SEA {
				V[i][j] = 1
				continue
			}

			// 未訪問の陸地が見つかったので
			// 島の数を1つ増やし、この陸地から辿れる陸地を訪問していく
			islands++
			queue.PushBack([]int{i, j})

			for queue.Len() > 0 {
				cur := queue.Remove(queue.Front()).([]int)
				h, w := cur[0], cur[1]
				if V[h][w] == 1 {
					continue
				}
				V[h][w] = 1

				// 全方向に未訪問の陸地がないか探索
				for v := -1; v <= 1; v++ {
					for l := -1; l <= 1; l++ {
						dh := h + v
						dw := w + l
						if M[dh][dw] == LAND && V[dh][dw] == 0 {
							queue.PushBack([]int{dh, dw})
						}
					}
				}
				/*
					if M[h-1][w] == LAND {
						queue.PushBack([]int{h - 1, w})
					}
					if M[h-1][w+1] == LAND {
						queue.PushBack([]int{h - 1, w + 1})
					}
					if M[h][w+1] == LAND {
						queue.PushBack([]int{h, w + 1})
					}
					if M[h+1][w+1] == LAND {
						queue.PushBack([]int{h + 1, w + 1})
					}
					if M[h+1][w] == LAND {
						queue.PushBack([]int{h + 1, w})
					}
					if M[h+1][w-1] == LAND {
						queue.PushBack([]int{h + 1, w - 1})
					}
					if M[h][w-1] == LAND {
						queue.PushBack([]int{h, w - 1})
					}
					if M[h-1][w-1] == LAND {
						queue.PushBack([]int{h - 1, w - 1})
					}
				*/
			}
		}
	}
	return islands
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	for {
		W, H := nextInt(sc), nextInt(sc)

		if W == 0 && H == 0 {
			break
		}
		// Initialize map and visted list
		M := make([][]int, H+2)
		V := make([][]int, H+2)
		for i := 0; i < H+2; i++ {
			M[i] = make([]int, W+2)
			V[i] = make([]int, W+2)
		}
		for i := 1; i <= H; i++ {
			for j := 1; j <= W; j++ {
				M[i][j] = nextInt(sc)
			}
		}

		islands := discoverIslands(M, V, H, W)

		fmt.Println(islands)
	}
}

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

def dfs(s,Map,H,W,c):
    dxdy = [(1,0),(-1,0),(0,1),(0,-1),(1,1),(-1,-1),(-1,1),(1,-1)]
    for i in range(len(dxdy)):
        Map[s[0]][s[1]] = c
        nextPos = (s[0]+dxdy[i][0],s[1]+dxdy[i][1])
        if nextPos[0] >= 0 and nextPos[1] >= 0 and nextPos[0] < H and nextPos[1] < W:
            if Map[nextPos[0]][nextPos[1]] == 1:
                dfs(nextPos,Map,H,W,c)

while True:
    W,H = map(int,input().split(" "))
    if W == 0 and H == 0:
        break
    Map = [list(map(int,input().split())) for i in range(0,H)]
    c = 1
    for i in range(H):
        for j in range(W):
            if Map[i][j] == 1:
                c += 1
                dfs((0,0),Map,H,W,c)
    print(c-1)

Python: #!python
# -*- coding: utf-8 -*-

import sys

import numpy as np

sys.setswitchinterval(10**8)


next_s = ((-1, 1), (0, 1), (1, 1),
          (-1, 0), (1, 0),
          (-1, -1), (0, -1), (1, -1))


def DFS(x, y):
    if not (0 <= x < W and 0 <= y < H):
        return
    if not map_[y, x]:
        return

    map_[y, x] = 0

    for dx, dy in next_s:
        DFS(x + dx, y + dy)


while True:
    W, H = map(int, input().split())
    if W == 0 and H == 0:
        break

    map_ = np.array([list(map(int, input().split())) for h in range(H)])
    # print(map_)
    island_num = 0
    while np.amax(map_):
        x = np.argmax(map_) % W
        y = np.argmax(map_) // W
        # print(map_)
        # print("x: {} | y: {}".format(x, y))
        DFS(x, y)
        island_num += 1

    print(island_num)

Python: import sys


class UnionFind:
    def __init__(self, n=0):
        self.d = [-1]*n
        self.u = n

    def root(self, x):
        if self.d[x] < 0:
            return x
        self.d[x] = self.root(self.d[x])
        return self.d[x]

    def unite(self, x, y):
        x, y = self.root(x), self.root(y)
        if x == y:
            return False
        if x > y:
            x, y = y, x
        self.d[x] += self.d[y]
        self.d[y] = x
        self.u -= 1
        return True

    def same(self, x, y):
        return self.root(x) == self.root(y)

    def size(self, x):
        return -self.d[self.root(x)]

    def num_union(self):
        return self.u


input = sys.stdin.readline
while True:
    W, H = map(int, input()[:-1].split())
    if W == 0:
        break
    S = [input()[:-1].split() for _ in [0]*H]

    uf = UnionFind(H*W)
    cnt = 0
    for h, ss in enumerate(S):
        for w, s in enumerate(ss):
            if s == '0':
                cnt += 1
                continue

            if h and w and S[h-1][w-1] == '1':
                uf.unite(h*W+w, (h-1)*W+w-1)
            if h and S[h-1][w] == '1':
                uf.unite(h*W+w, (h-1)*W+w)
            if h and w+1<W and S[h-1][w+1] == '1':
                uf.unite(h*W+w, (h-1)*W+w+1)
            if w and S[h][w-1] == '1':
                uf.unite(h*W+w, h*W+w-1)


    print(uf.u-cnt)

Python: import queue
def allvisited():
    for i in range(w):
        for j in range(h):
            if (visited[i][j]==False and s[i][j]=='1'):
                return (False,i,j)
    else:
         return (True,-1,-1)
        
def legal(pos):
    if(0<=pos[0]<w) and (0<=pos[1]<h) and s[pos[0]][pos[1]]=='1' and visited[pos[0]][pos[1]]==False:
        return True
    else:
        return False
    
d=[[0,1],[0,-1],[1,0],[-1,0],[1,1],[-1,1],[1,-1],[-1,-1]]
while(1):
    h,w=map(eval,input().split())
    if (w==0 and h==0): break
    s=[]
    for i in range(w):
        s.append(input().split())
    #print(s)
    Q=queue.Queue()
    visited=[]
    for i in range(w):
        visited.append([False]*h)
    #print(visited)
    count=0
    while(1):
        a=allvisited()
        if (a[0]==False):
            Q.put((a[1],a[2]))
            count+=1
        else:
            break
        while(not Q.empty()):
            now=Q.get()
            visited[now[0]][now[1]]=True
            for i in range(8):
                new=(now[0]+d[i][0],now[1]+d[i][1])
                if(legal(new)):
                    Q.put(new)
    print(count)

Python: import sys
readline = sys.stdin.buffer.readline

from collections import deque
import copy

def myinput():
    return map(int,readline().split())

def mycol(data,col):
    return [ row[col] for row in data ]

ls_ans = []

w,h = myinput()
c = [ list(myinput()) for _ in range(h) ]

while w!=0 or h!=0:
    def dfs(sx,sy):
        stack = deque()
        stack.append([sx,sy])
        while stack:
            x,y = stack.pop()
            if c[x][y]==1:
                c[x][y] = 0
                for i in range(-1,2):
                    for j in range(-1,2):
                        if i==0 and j==0:
                            continue
                        else:
                            nx = x + i
                            ny = y + j
                            if nx==-1 or ny==-1 or nx==h or ny==w:
                                pass
                            else:
                                if c[nx][ny]==1:
                                    stack.append([nx,ny])
                                else:
                                    pass
            else:
                pass

    ans = 0
    for i in range(h):
        for j in range(w):
            if c[i][j]==1:
                dfs(i,j)
                ans += 1
            else:
                pass
    # print(ans)
    ls_ans.append(ans)

    w,h = myinput()
    c = [ list(myinput()) for _ in range(h) ]

for i in range(len(ls_ans)):
    print(ls_ans[i])