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 <vector>
#include <utility>
using namespace std;

struct UnionFind {
    vector<int> data;
    int sz;
    UnionFind(int sz) : data(sz, -1), sz(sz){ }
    bool unionSet(int x, int y) {
        if ((x = root(x)) == (y = root(y))) return false;
        if (data[x] > data[y]) swap(x, y);
        data[x] += data[y]; data[y] = x; sz--;
        return true;
    }
    bool findSet(int x, int y) { return root(x) == root(y); }
    int root(int x) { return data[x] < 0 ? x : data[x] = root(data[x]); }
    int size(int x) { return -data[root(x)]; }
    int size() { return sz; }
};

int main() {
  int w, h;
  while (cin >> w >> h) {
    if (w == 0 && h == 0) {
      break;
    }
    int count = 0;
    vector<vector<int>> c(h, vector<int>(w));
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        cin >> c[i][j];
        if (c[i][j] == 0) {
          count++;
        }
      }
    }
    auto idx = [&](int i, int j) {
      return i*w + j;
    };
    auto outfield = [&](int i, int j) {
      return i < 0 || i >= h || j < 0 || j >= w;
    };
    UnionFind uf(w*h);
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        for (int x = -1; x <= 1; x++) {
          for (int y = -1; y <= 1; y++) {
            if (outfield(i + x, j + y)) {
              continue;
            }
            if (c[i][j] == 1 && c[i + x][j + y] == 1) {
              uf.unionSet(idx(i, j), idx(i + x, j + y));
            }
          }
        }
      }
    }
    cout << uf.size() - count << endl;
  }
}

C++: #include <iostream>

using namespace std;

bool isVisited[50][50] = { false };
int isLand[50][50] = { 0 };

void dfs(int x, int y, int w, int h)
{
  if (x < 0 || x >= w || y < 0 || y >= h) return;
  if (isVisited[x][y] == true) return;
  if (isLand[x][y] == 0) return;

  isVisited[x][y] = true;

  int dx[8] = { -1, 0, 1, -1, 1, -1,  0,  1 };
  int dy[8] = {  1, 1, 1,  0, 0, -1, -1, -1 };

  for (int i = 0; i < 8; i++) {
    dfs(x + dx[i], y + dy[i], w, h);
  }
}

int main()
{
  int w, h;
  while (1) {
    cin >> w >> h;
    if (w == 0 && h == 0) break;
    
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        cin >> isLand[j][i];
        isVisited[j][i] = false;
      }
    }

    int count = 0;
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        if (isVisited[j][i] == false && isLand[j][i] == 1) {
          dfs(j, i, w, h);
          count++;
        }
      }
    }
    cout << count << endl;
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0; i < n; i++)
#define FOR(i, m, n) for(ll i = m; i < n; i++)
#define all(vec) vec.begin(), vec.end()
#define tmax(x, y, z) max((x), max((y), (z)))
#define tmin(x, y, z) min((x), min((y), (z)))
ll MM = 1000000000; ll mod = MM + 7; ll MMM=9223372036854775807;//2^63 -1
ll GCD(ll x, ll y){ if(y == 0) return x; else return GCD(y, x % y);}
ll LCM(ll x, ll y){ return x / GCD(x, y) * y;}
template<class T> inline bool chmin(T& a, T b){ if(a > b){ a = b; return true;} return false;}
template<class T> inline bool chmax(T& a, T b){ if(a < b){ a = b; return true;} return false;}
const ll INF = 1LL << 60;
using Graph = vector<vector<ll>>;
int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int ddx[8] = {1, 1, 0, -1, -1, -1, 0, 1}, ddy[8] = {0, 1, 1, 1, 0, -1, -1, -1};
//cout << fixed << setprecision(10);

int field[100][100];
ll w, h;


void dfs(ll y, ll x){
    field[y][x] = 0;
    rep(i, 8){
        ll ny = y + ddy[i], nx = x + ddx[i];
        if(0 <= ny && ny < h && 0 <= nx && nx < w && field[ny][nx]){
            dfs(ny, nx);
        }
    }
}


int main(){
    while(1){
        cin >> w >> h;
        if(!w && !h) break;
        rep(hi, h){
            rep(wi, w){
                cin >> field[hi][wi];
            }
        }

        ll ans = 0;
        rep(hi, h){
            rep(wi, w){
                if(field[hi][wi]){
                    dfs(hi, wi);
                    ans++;
                }
            }
        }

        cout << ans << endl;
    }
}