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>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) FOR(i,0,n)
#define repr(i,n) for(int i=(n)-1;0<=i;--i)
#define each(e,v) for(auto&& e:(v))
#define all(v) begin(v),end(v)
#define dump(x) cerr<<#x<<": "<<(x)<<endl
#define INF 100000000
#define IINF 9999999999999;
using vint = vector<int>;
using ll = long long;
using vll = vector<ll>;
template <class T> void chmin(T& a, const T& b) { a = min(a, b); }
template <class T> void chmax(T& a, const T& b) { a = max(a, b); }

bool earth[51][51];

void erase_island(int h, int w) {
    earth[h][w] = false;
    //cout << "# " << h << " " << w << endl;
    if(earth[h - 1][w - 1]) erase_island(h - 1, w - 1);
    if(earth[h - 1][w]) erase_island(h - 1, w);
    if(earth[h - 1][w + 1]) erase_island(h - 1, w + 1);
    if(earth[h][w + 1]) erase_island(h, w + 1);
    if(earth[h + 1][w + 1]) erase_island(h + 1, w + 1);
    if(earth[h + 1][w]) erase_island(h + 1, w);
    if(earth[h + 1][w - 1]) erase_island(h + 1, w - 1);
    if(earth[h][w - 1]) erase_island(h, w - 1);
}

int main() {
    //ofstream outputfile("output.txt");
    while(true) {
        int w = 0, h = 0;
        cin >> w >> h;
        if(w == 0 && h == 0) break;
        int temp;
        rep(i, h) {
            rep(j, w) {
                cin >> temp;
                if(temp == 0) earth[i][j] = false;
                else earth[i][j] = true;
            }
        }

        int ans = 0;
        rep(i, h) {
            rep(j, w) {
                if(earth[i][j]) {
                    erase_island(i, j);
                    ++ans;
                }
            }
        }

        cout << ans << endl;
    }

    return 0;
}

C++: #define  _USE_MATH_DEFINES
#define  _USE_MATH_DEFINES

#define  rep(i, n) for(int i = 0; i < n; i++)
#define  repx(i, a, n) for(int i = a; i < n; i++)
#define  loop while(1)
#define  lli long long int
#define  aryout(ary) rep(i, ary.size()) cout << ary[i] << (i < ary.size() - 1 ? " " : "\n");
 
#include <iostream>
#include <algorithm>
#include <cmath>
#include <numeric>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <list>
#include <map>
#include <utility>
#include <set>

using namespace std;

void dfs (vector<vector<int>> &umi, int h, int w, int i, int j) {
  umi[i][j] = 2;
  for (int di = -1; di <= 1; di++)
    for (int dj = -1; dj <= 1; dj++)
      if (umi[i + di][j + dj] == 1)
        dfs (umi, h, w, i + di, j + dj);
}

int bfs (vector<vector<int>> &umi, int h, int w) {
  int cnt = 0;
  stack<vector<int>> gnd;
  vector<int> tmp0(2, 0);
  vector<int> tmp1(2, 0);

  repx (i, 1, h + 1) repx (j, 1, w + 1) {
    if (umi[i][j] == 1) {
      umi[i][j] = 2;
      cnt += 1;
      tmp0[0] = i; tmp0[1] = j;
      gnd.push(tmp0);

      while (gnd.size() > 0) {
        tmp0[0] = gnd.top()[0];
        tmp0[1] = gnd.top()[1];
        gnd.pop();

        //cout << "cnt: " << cnt << endl;
        //repx (i, 0, h + 2) repx (j, 0, w + 2)
          //cout << umi[i][j] << (j < w + 1 ? " " : "\n");

        umi[tmp0[0]][tmp0[1]] = 2;
        for (int di = -1; di <= 1; di++) {
          for (int dj = -1; dj <= 1; dj++) {
            tmp1[0] = tmp0[0] + di; tmp1[1] = tmp0[1] + dj;
            if (umi[tmp1[0]][tmp1[1]] == 1) {
              gnd.push(tmp1);
              umi[tmp1[0]][tmp1[1]] = 2;
              //cout << tmp1[0] << " " << tmp1[1] << " (" << umi[tmp1[0]][tmp1[1]] << ") " <<  "has pushed." << endl;
            }
          }
        }
      }
    }
  }
  return cnt;
}


int main() {

  int w, h;
  
  loop {
    cin >> w >> h;
    if (w + h == 0) break;

    vector<vector<int>> umi(h + 2, vector<int>(w + 2, 0));
    rep (i, h) rep (j, w) cin >> umi[i + 1][j + 1];

    /*
    int cnt_by_DFS = 0;
    repx (i, 1, h + 1) repx (j, 1, w + 1) {
      if (umi[i][j] == 1) {
        cnt_by_DFS += 1;
        dfs (umi, h, w, i, j);
      }
    }
    cout << cnt_by_DFS << endl;
    */
    cout << bfs (umi, h, w) << endl;
  }

  return 0;
}