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 <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <string>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>

#define rep(i,j) REP((i), 0, (j))
#define REP(i,j,k) for(int i=(j);(i)<(k);++i)
#define between(a,x,b) ((a)<=(x)&&(x)<=(b))
#define ck(i, x) ((i) >= 0 && (i) < (x))
using namespace std;
int w, h;
int area[51][51];
int dx[] = {-1,0,1}, dy[] = {-1,0,1};
void dfs(int y, int x){
  area[y][x] = 0;
  //  printf("%d %d\n", y, x);
  rep(i, 3) rep(j, 3)
    if(ck(y+dy[i], h) && ck(x+dx[j], w) && area[y+dy[i]][x+dx[j]]) dfs(y+dy[i], x+dx[j]);

  return;
}
int main(){
  while(scanf("%d%d", &w, &h) && w && h){
    //    printf("in area\n");
    rep(i, h) rep(j, w) scanf("%d", &area[i][j]);
    int cnt = 0;
    //    puts("start solve");
    rep(i, h) rep(j, w) if(area[i][j]) dfs(i, j), cnt++;
    //    puts("end solve");
    printf("%d\n", cnt);
  }
  return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define fi first
#define se second
#define FOR(i, a, b) for(int i=(a);i<(b);i++)
#define REP(i, n) FOR(i, 0, n)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define RREP(i, n) FOR(i, n, 0)
#define MFOR(i, m) for(auto i=(m).begin();i!=(m).end();i++)
#define ALL(a) (a).begin(), (a).end()
#define SZ(x) ((int)(x).size())

typedef long long int ll;
typedef pair<int, int> P;
typedef vector<int> vi;
typedef vector<vi> vvi;

const double eps = 1e-10;
const int MOD = 1000000007;

template<typename T>
void printv(vector<T> const& s) {
  REP(i, s.size()) {
    cout << s[i] << " ";
  }
  cout << endl;
}

int main () {
  cin.tie(0);
  cout << setprecision(10);

  
  while(1) {
    int w, h; cin >> w >> h;
    if(w == 0 && h == 0) break;
    vector<vector<bool>> c(h);
    int tmp = 0;
    REP(i, h) {
      c[i].resize(w);
      REP(j, w) {
        cin >> tmp;
        c[i][j] = (tmp == 1);
      }
    }

    int cnt = 0;
    vector<vector<bool>> sel(h);
    REP(i, h) {
      sel[i].resize(w, false);
    }

    REP(i, h) {
      REP(j, w) {
        if(!sel[i][j] && c[i][j]) {
          P st = make_pair(i, j);
          // cout << i << ":" << j << endl;
          vi dx = {-1, 0, 1}, dy = {-1, 0, 1};
          queue<P> q;
          q.push(st);
          sel[i][j] = true;
          while(!q.empty()) {
            P now = q.front();q.pop();
            REP(k, 3) {
              REP(l, 3) {
                int tmpx = now.fi + dx[k], tmpy = now.se + dy[l];
                if(0 <= tmpx && tmpx <= h-1 &&
                   0 <= tmpy && tmpy <= w-1 &&
                   !sel[tmpx][tmpy] && c[tmpx][tmpy] && (dx[k] != 0 || dy[l] != 0)) {
                  q.push(make_pair(tmpx, tmpy));
                  sel[tmpx][tmpy] = true;
                }
              }
            }
          }
          cnt++;
        }
      }
    }

    cout << cnt << endl;
  }

}

C++: #include<bits/stdc++.h>
using namespace std;
#define OUT(x) cout<<x<<endl
#define DEBUG(x) cout<<#x<<": "<<x
const int BA = 1000;
const int INFTY = (1<<21);
int c[51][51];
int w,h;
int del(int x,int y){
  if(x<0 || y<0 || x>=w || y>= h)return 0;
  if(c[x][y]){
    c[x][y] = 0;
    return del(x+1,y)+del(x,y+1)+del(x+1,y+1)+
      del(x-1,y-1)+del(x-1,y)+del(x,y-1)+del(x+1,y-1)+del(x-1,y+1);
    
  }
  else return 0;
  
}
int solve(int x,int y){
  if(x==0 && y == h)return 0;
  else if(x==w){
    return solve(0,y+1);
  }
  else if(c[x][y]==1){
    del(x,y);
    return solve(x+1,y)+1;
  }
  else return solve(x+1,y);
}
int main(){
  while(cin>>w>>h&&w&&h){
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
	cin >> c[i][j];
      }
    }
    
    cout << solve(0,0) << endl;
  }
}