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 <string>
#include <vector>
using namespace std;
int w,h;
vector<int> nx;
vector<int> ny;
bool check(int **field){
  nx.clear();
  ny.clear();
  for (int i=0;i<h;i++){
    for (int j=0;j<w;j++){
      if (field[i][j]==1){
	nx.push_back(i);
	ny.push_back(j);
	return true;
      }
    }
  }
  return false;
}
void find(int **field){
  int x[nx.size()];
  int y[ny.size()];
  int s=nx.size();
  for (int i=0;i<s;i++){
    field[nx[i]][ny[i]]=0;
    x[i]=nx[i];
    y[i]=ny[i];
  }
  nx.clear();
  ny.clear();
  for (int i=0;i<s;i++){
    if (field[x[i]+1][y[i]]==1&&x[i]+1<h){
      nx.push_back(x[i]+1);
      ny.push_back(y[i]);
    }
    if (field[x[i]-1][y[i]]==1&&x[i]-1>=0){
      nx.push_back(x[i]-1);
      ny.push_back(y[i]);
    }
    if (field[x[i]][y[i]+1]==1&&y[i]+1<w){
      nx.push_back(x[i]);
      ny.push_back(y[i]+1);
    }
    if (field[x[i]][y[i]-1]==1&&y[i]-1>=0){
      nx.push_back(x[i]);
      ny.push_back(y[i]-1);
    }
    if (field[x[i]+1][y[i]+1]==1&&x[i]+1<h&&y[i]+1<w){
      nx.push_back(x[i]+1);
      ny.push_back(y[i]+1);
    }
    if (field[x[i]+1][y[i]-1]==1&&x[i]+1<h&&y[i]-1>=0){
      nx.push_back(x[i]+1);
      ny.push_back(y[i]-1);
    }
    if (field[x[i]-1][y[i]+1]==1&&x[i]-1>=0&&y[i]+1<w){
      nx.push_back(x[i]-1);
      ny.push_back(y[i]+1);
    }
    if (field[x[i]-1][y[i]-1]==1&&x[i]-1>=0&&y[i]-1>=0){
      nx.push_back(x[i]-1);
      ny.push_back(y[i]-1);
    }
  }
  if (nx.empty()){
    return;
  }
  int *f[h];
  for (int i=0;i<h;i++)
    f[i]=field[i];
  return find(f);
}
int main(){
  while (cin>>w>>h,w|h!=0){
    int count=0;
    int field[h][w];
    for (int i=0;i<h;i++){
      for (int j=0;j<w;j++){
	cin>>field[i][j];
      }
    }
    int *f[h];
    for (int i=0;i<h;i++) 
      f[i]=field[i];
    while (check(f)){
      find(f);
      count++;
      }
    cout<<count<<endl;
  }
}

C++: #pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
using namespace::std;
#define rep(i, n) for(lint i = 0; i < (lint)(n); i++)
#define repi(i,a,b) for(lint i=lint(a);i<lint(b);i++)
typedef long long lint;
struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}} __init;
template<typename T=lint> T in(){
    return *istream_iterator<T>(cin);
}

vector<lint> dx={-1,1,0,0,1,1,-1,-1};
vector<lint> dy={0,0,-1,1,1,-1,1,-1};
int main(){
    while(1){
        lint w,h;
        cin>>w>>h;
        if(w==0&&h==0)break;
        vector<vector<lint>>v(h,vector<lint>(w));
        rep(i,h)rep(j,w){
            cin>>v[i][j];
        }
        lint ans=0;
        rep(i,h)rep(j,w){
            if(v[i][j]==0)continue;
            ans++;
            stack<pair<lint,lint>>s;
            s.emplace(i,j);
            while(!s.empty()){
                lint r,c;
                tie(r,c)=s.top();
                s.pop();
                rep(k,8){
                    if(r+dy[k]<0||h<=r+dy[k]||c+dx[k]<0||w<=c+dx[k])continue;
                    if(v[r+dy[k]][c+dx[k]]==1){
                        v[r+dy[k]][c+dx[k]]=0;
                        s.emplace(r+dy[k],c+dx[k]);
                    }
                }
            }
        }
        cout<<ans<<endl;
    }
}

C++: 
#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#define unsigned long long 
#define rep(i,a,b) for(ull (i)=(a);(i)<(b);i++)
void dfs(int w, int h);
using namespace std;
int field[50][50];
int x, y;
int cnt;
int main(void){
	while (true){
		cin >> x >> y;
		if (x == 0)
			break;
		cnt = 0;
		for (int i = 0; i < y; i++){
			for (int j = 0; j < x; j++){
				cin >> field[i][j];
			}
		}
		for (int i = 0; i < y; i++){
			for (int j = 0; j < x; j++){
				if (field[i][j] == 1){
					cnt++;
					dfs(i, j);
				}
			}
		}
		cout << cnt << endl;
	}
	return 0;
}


void dfs(int h, int w){
	field[h][w] = 0;

	if (w < x - 1){
		if (field[h][w + 1] == 1){
			dfs(h, w + 1);
		}
	}
	if (w < x - 1&&h<y-1){
		if (field[h+1][w + 1] == 1){
			dfs(h+1 ,w + 1);
		}
	}
	if (h<y - 1){
		if (field[h+ 1][w ] == 1){
			dfs(h +1 ,w );
		}
	}
	if (h<y - 1&&w>0){
		if (field[h + 1][w-1] == 1){
			dfs(h + 1, w-1);
		}
	}
	if (w>0){
		if (field[h ][w - 1] == 1){
			dfs(h , w - 1);
		}
	}
	if (w>0&&h>0){
		if (field[h-1][w - 1] == 1){
			dfs(h-1, w - 1);
		}
	}
	if (h>0){
		if (field[h - 1][w] == 1){
			dfs(h - 1, w);
		}
	}
	if (h>0&&w<x-1){
		if (field[h - 1][w+1] == 1){
			dfs(h - 1, w+1);
		}
	}
}