Go: package main

import (
	"bufio"
	"fmt"
	"io"
	"math"
	"os"
	"strconv"
)

var (
	readString func() string
	readBytes  func() []byte
	stdout     *bufio.Writer
)

func init() {
	readString, readBytes = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func newReadString(ior io.Reader) (func() string, func() []byte) {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), math.MaxInt32)
	r.Split(bufio.ScanWords)

	f1 := func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
	f2 := func() []byte {
		return []byte(f1())
	}
	return f1, f2
}

func readInt() int {
	return int(readInt64())
}

func readInt64() int64 {
	i, err := strconv.ParseInt(readString(), 10, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func readFloat64() float64 {
	f, err := strconv.ParseFloat(readString(), 64)
	if err != nil {
		panic(err.Error())
	}
	return f
}

func printf(f string, args ...interface{}) (int, error) {
	return fmt.Fprintf(stdout, f, args...)
}

func println(args ...interface{}) (int, error) {
	return fmt.Fprintln(stdout, args...)
}

func eprintln(args ...interface{}) (int, error) {
	return fmt.Fprintln(os.Stderr, args...)
}

func eprintf(f string, args ...interface{}) (int, error) {
	return fmt.Fprintf(os.Stderr, f, args...)
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func min64(a, b int64) int64 {
	if a < b {
		return a
	}
	return b
}

func max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

func max64(a, b int64) int64 {
	if a < b {
		return b
	}
	return a
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

func abs64(a int64) int64 {
	if a < 0 {
		return -a
	}
	return a
}

func gcd(a, b int) int {
	if b == 0 {
		return a
	}
	return gcd(b, a%b)
}

func gcd64(a, b int64) int64 {
	if b == 0 {
		return a
	}
	return gcd64(b, a%b)
}

// readString() string
// readInt() int
// readInt64() int64
// readFloat64() float64

// -----------------------------------------------------------------------------

func main() {
	defer stdout.Flush()

	for {
		ans, ok := solve()
		if !ok {
			break
		}
		println(ans)
	}

}

func solve() (int, bool) {
	w := readInt()
	h := readInt()
	if w == 0 && h == 0 {
		return 0, false
	}

	c := make([][]int, h+2)
	c[0] = make([]int, w+2)
	c[h+1] = make([]int, w+2)
	for i := 1; i-1 < h; i++ {
		c[i] = make([]int, w+2)
		for j := 1; j-1 < w; j++ {
			c[i][j] = readInt()
		}
	}

	var ans int
	for i := 1; i-1 < h; i++ {
		for j := 1; j-1 < w; j++ {
			if 0 < c[i][j] {
				ans++
				dfs(c, i, j)
			}
		}
	}
	return ans, true
}

func dfs(c [][]int, y, x int) {
	c[y][x] = 0
	dx := []int{-1, 0, 1, -1, 1, -1, 0, 1}
	dy := []int{-1, -1, -1, 0, 0, 1, 1, 1}
	for i := range dx {
		nx := x + dx[i]
		ny := y + dy[i]
		if 0 < c[ny][nx] {
			dfs(c, ny, nx)
		}
	}
}

// -----------------------------------------------------------------------------

C++: #include <iostream>
#include <fstream>
#include <cstdlib>
#include <math.h>
#include <utility>
#include <algorithm>
#include <functional>
#include <vector>
#include <numeric>
#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;
using vb = vector<bool>;
using Graph = vector<vector<int>>;

#define FOR(i, a, b) for (int i = a; i < (b); i++)
#define REP(i,n) for(int i=0;i<n;i++)

vb seen;

void dfs(const Graph &G, int v) {
    seen[v] = true;
    for(auto next_v : G[v]) {
        if (seen[next_v]) continue;
        dfs(G, next_v);
    }
}

int main () {
	cin.tie(0);
   	ios::sync_with_stdio(false);

    int w, h;
    while(cin >> w >> h, w*h) {
        int map[h+1][w+1];
        REP(j, w+1) {
            map[0][j] = 0;
        }
        REP(i, h) {
            map[i+1][0] = 0;
            REP(j, w) {
                cin >> map[i+1][j+1];
            }
        }
        
        Graph G(w*h);
        FOR(i, 1, h+1) {
            FOR(j, 1, w+1) {
                if (map[i][j] == 1) {
                    int p1 = (i-1)*w+(j-1);
                    int p2;
                    if (map[i][j-1] == 1) {
                        p2 = (i-1)*w+(j-2);
                        G[p1].push_back(p2);
                        G[p2].push_back(p1);
                    }
                    if (map[i-1][j-1] == 1) {
                        p2 = (i-2)*w+(j-2);
                        G[p1].push_back(p2);
                        G[p2].push_back(p1);
                    }
                    if (map[i-1][j] == 1) {
                        p2 = (i-2)*w+(j-1);
                        G[p1].push_back(p2);
                        G[p2].push_back(p1);
                    }
                    if (map[i-1][j+1] == 1) {
                        p2 = (i-2)*w+j;
                        G[p1].push_back(p2);
                        G[p2].push_back(p1);
                    }
                }
            }
        }

        seen.assign(w*h, false);
        int cnt = 0;
        REP(i, w*h) {
            if (seen[i]) continue;
            if (map[i/w+1][i%w+1] == 0) {
                seen[i] = true;
                continue;
            }
            cnt++;
            dfs(G, i);
        }
        cout << cnt << "\n";
    }
}

C++: #include<iostream>
#include<queue>

typedef std::pair<int, int> P;
int vx[] = { 0, 1, 0, -1, 1, 1, -1, -1 }, vy[] = { 1, 0, -1, 0, 1, -1, 1, -1 };
int w, h;
int map[51][51];

void bfs(int x, int y){

	map[y][x] = 0;

	std::queue<P>que;
	que.push(P(x, y));

	while (!que.empty()){

		P p = que.front();
		que.pop();

		for (int i = 0; i < 8; i++){
			int nx = p.first + vx[i], ny = p.second + vy[i];

			if (0 <= nx&&nx < w && 0 <= ny&&ny < h&&map[ny][nx] != 0){
				map[ny][nx] = 0;
				que.push(P(nx, ny));
			}
		}
	}

	return;
}

int main(){

	while (std::cin >> w >> h, w || h){

		int cnt = 0;

		memset(map, 0, sizeof(map));

		for (int i = 0; i < h; i++){
			for (int j = 0; j < w; j++){
				std::cin >> map[i][j];
			}
		}

		for (int i = 0; i < h; i++){
			for (int j = 0; j < w; j++){
				if (map[i][j] != 0){
					bfs(j, i);
					cnt++;
				}
			}
		}

		std::cout << cnt << std::endl;
	}

	return 0;
}

C++: #include <iostream>
using namespace std;

int H, W;
int field[51][51];

//動的計画法
void dfs(int h, int w){
    field[h][w] = 0;

    //八方向を１つずつ探索
    for(int dh = -1; dh <= 1; dh++){
        for(int dw = -1; dw <= 1; dw++){
            int nh = h + dh;
            int nw = w + dw;

            //場外アウトまたは０ならば、それ以降（再帰的に探索する部分）は実行せずループの最初に戻る
            if(nh < 0 || nh > H || nw < 0 || nw > W || field[nh][nw] == 0) continue;

            //再帰的に探索（探索しているマスを基準にしてその八方向にあるマスを探索していく）
            dfs(nh, nw);
        }
    }
}

int main(void){
    while(true){
        cin >> W >> H;
        if(W + H == 0) break;

        for(int i = 0; i < H; i++){
            for(int j = 0; j < W; j++){
                cin >> field[i][j];
            }
        }

        //探索開始
        int c = 0; //島の個数
        for(int i = 0; i < H; i++){
            for(int j = 0; j < W; j++){
                if(field[i][j] == 0) continue; //島の一部でないならば、それ以降スルー
                dfs(i, j); //そのマスが陸であるならば、その八方向を動的計画法で探索していく
                c++;
            }
        }
        cout << c << endl;
    }
}