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 <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for(int i = 0; i < n; i++)
#define all(a) a.begin(), a.end()
#define P pair<int, int>
#define F first
#define S second
#define prime 1000000007
#define INF 40000000000000000
int dx8[8] = {-1, 0, 1, 1, 1, 0, -1, -1};
int dy8[8] = {1, 1, 1, 0, -1, -1, -1, 0};
int dx4[4] = {-1, 0, 1, 0};
int dy4[4] = {0, -1, 0, 1};
bool Grid[51][51];
int w, h;
void dfs(int x, int y) {
    //cout << x << ':' << y << "HaHaHaHa" << endl;
    rep(i, 8) {
        int nx = x + dx8[i];
        int ny = y + dy8[i];
        //cout << x << ':' << dx8[i] << ' ' << y << ':' << dy8[i] << ' ' << nx << ':' << ny << endl;
        if(nx < 0 || nx >= h || ny < 0 || ny >= w) continue;
        if(Grid[nx][ny]) {
            Grid[nx][ny] = false;
            dfs(nx, ny);
        }
    }
}
signed main(void) {
    while(true) {
        cin >> w >> h;
        if(w == 0 && h == 0) return 0;
        rep(i, 51) rep(j, 51) Grid[i][j] = false;
        rep(i, h) rep(j, w) {
            int x;
            cin >> x;
            if(x == 1) Grid[i][j] = true;
        }
        int ans = 0;
        rep(i, h) rep(j, w) {
            if(Grid[i][j]) {
                ans++;
                Grid[i][j] = false;
                dfs(i, j);
            }
        }
        cout << ans << endl;
    }
}

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

int f[64][64] = {0};
int dx[] = {0,0,1,1,1,-1,-1,-1};
int dy[] = {1,-1,0,1,-1,0,1,-1};

void dfs(int y, int x)
{
	f[y][x] = 0;
	for(int i=0; i<8; i++)
	{
		int ny = y+dy[i];
		int nx = x+dx[i];
		if(f[ny][nx])
		{
			dfs(ny,nx);
		}
	}
}

int main()
{
	int w,h,c,x,y;
	while(cin >> w >> h, w||h)
	{
		memset(f,0,sizeof(f));

		for(y=1; y<=h; y++)
		for(x=1; x<=w; x++)
		{
			cin >> f[y][x];
		}

		c=0;
		for(y=1; y<=h; y++)
		for(x=1; x<=w; x++)
		{
			if(f[y][x])
			{
				c++;
				dfs(y,x);
			}
		}
		cout << c << endl;
	}
}