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)
	}
}

C++: #include <bits/stdc++.h>
#ifdef _DEBUG
#include "../../../debug_print.hpp"
#else
#define debug(...)
#endif
#define sort_(a) sort(a.begin(), a.end())
#define rsort(a) sort(a.rbegin(), a.rend())
#define rep(i, n) for (int i = 0; i < n; i++)
#define rrep(i, n) for (int i = n - 1; 0 <= i; i--)
#define for_(i, start, end) for (int i = start; i < end; i++)
#define rfor(i, start, end) for (int i = start - 1; 0 <= i; i--)
#define all(a) a.begin(), a.end()
using ll = long long;
using ld = long double;
using namespace std;
constexpr int INF32       = 1'050'000'000;
constexpr long long INF64 = 4'000'000'000'000'000'000;
constexpr int MOD7        = 1'000'000'007;
constexpr int MOD53       = 998'244'353;
constexpr double PI       = 3.14159265358979323846;
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;
}
void print() { std::cout << '\n'; }
template <class H, class... T> void print(H &&head, T &&... args) {
    std::cout << head;
    sizeof...(args) == 0 ? std::cout << "" : std::cout << ' ';
    print(std::forward<T>(args)...);
}
template <class T> void print(std::vector<T> &v) {
    for (int i = 0; i < v.size(); i++) {
        std::cout << v[i];
        i == v.size() - 1 ? std::cout << '\n' : std::cout << ' ';
    }
}
template <class T> void print(std::vector<std::vector<T>> &v) {
    for (int i = 0; i < v.size(); i++) {
        for (int j = 0; j < v[i].size(); j++) {
            std::cout << v[i][j];
            j == v[i].size() - 1 ? std::cout << '\n' : std::cout << ' ';
        }
    }
}
void scan() {}
template <class H, class... T> void scan(H &&head, T &&... args) {
    std::cin >> head;
    scan(std::forward<T>(args)...);
}
template <class T> void scan(std::vector<T> &v) {
    for (auto &&i : v) {
        scan(i);
    }
}

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

    while (true) {
        int w, h;
        scan(w, h);
        if (w == 0 && h == 0)
            break;
        vector<vector<int>> mp(h, vector<int>(w));
        scan(mp);
        int ans        = 0;
        vector<int> dx = {-1, -1, -1, 0, 0, 1, 1, 1};
        vector<int> dy = {-1, 0, 1, -1, 1, -1, 0, 1};
        auto exist     = [](int H, int W, int nx, int ny) -> bool {
            if (nx < 0 || W <= nx || ny < 0 || H <= ny)
                return false;
            else
                return true;
        };
        auto dfs = [&](auto f, int y, int x) -> void {
            mp[y][x] = 0;
            rep(i, dx.size()) {
                int nx = x + dx[i];
                int ny = y + dy[i];
                if (exist(h, w, nx, ny) && mp[ny][nx] == 1) {
                    f(f, ny, nx);
                }
            }
            return;
        };
        rep(y, h) {
            rep(x, w) {
                if (mp[y][x] == 1) {
                    dfs(dfs, y, x);
                    ans++;
                }
            }
        }
        print(ans);
    }

    return 0;
}

C++: #include <bits/stdc++.h>
 
using namespace std;
 
int c[64][64];
 
void paint(int y, int x) {
  if (y < 0 || y >= 50 || x < 0 || x >= 50) return;
  if (c[y][x] == 0) return;
  c[y][x] = 0;
  for (int dy = -1; dy <= 1; ++dy) {
    for (int dx = -1; dx <= 1; ++dx) {
      paint(y + dy, x + dx);
    }
  }
}
 
int main() {
  int H, W;
  while (cin >> W >> H, H) {
    for (int i = 0; i < H; ++i) {
      for (int j = 0; j < W; ++j) {
        cin >> c[i][j];
      }
    }
    int res = 0;
    for (int y = 0; y < H; ++y) {
      for (int x = 0; x < W; ++x) {
        if (c[y][x] == 1) {
          ++res;
          paint(y, x);
        }
      }
    }
    cout << res << endl;
  }
  return 0;
}