Go: ///
// File:  1160.go
// Author: ymiyamoto
//
// Created on Sun Mar  4 20:45:57 2018
//
package main

import (
	"fmt"
)

var w, h int
var graph [][]string

func dfs(visited [][]bool, x, y int) {
	visited[x][y] = true

	for i := -1; i <= 1; i++ {
		for j := -1; j <= 1; j++ {
			dx := x + i
			dy := y + j
			if 0 <= dx && dx < h && 0 <= dy && dy < w && graph[dx][dy] == "1" && !visited[dx][dy] {
				dfs(visited, dx, dy)
			}
		}
	}
}

func main() {
	for {
		fmt.Scan(&w, &h)
		if w == 0 && h == 0 {
			break
		}

		graph = make([][]string, h)
		for i := range graph {
			graph[i] = make([]string, w)
		}

		for i := 0; i < h; i++ {
			for j := 0; j < w; j++ {
				var s string
				fmt.Scan(&s)
				graph[i][j] = s
			}
		}

		visited := make([][]bool, h)
		for i := range visited {
			visited[i] = make([]bool, w)
		}

		count := 0
		for i := range graph {
			for j := range graph[i] {
				if graph[i][j] == "1" && !visited[i][j] {
					dfs(visited, i, j)
					count++
				}
			}
		}

		fmt.Println(count)
	}
}

C++: #include <bits/stdc++.h>
#define rep(i,n)    for(long long i = 0; i < (n) ; ++i)
#define orep(i,n)   for(long long i = 1; i <= (n); ++i)   // one rep
#define drep(i,n)   for(long long i = (n)-1; i >= 0; --i) // down rep
#define srep(i,s,t) for(long long i = (s); i < (t); ++i)  // set rep
#define rng(x)  (x).begin(),(x).end()

  // range
#define rrng(a) (a).rbegin(),(a).rend() // reverse range
#define isin(x,l,r) ((l) <= (x) && (x) < (r))
#define ru(x,y) (((x)+(y)-1)/(y)) // round up
#define fi first
#define se second
#define eb emplace_back
#define fcout cout << fixed << setprecision(15)


using namespace std;
using ll  = long long;
using P   = pair<int,int>;
using vi  = vector<int>;
using vvi = vector<vi>;
using vp  = vector<P>;
using vl  = vector<ll>;

template<typename T> void Yes(T flag) {
  cout << (flag ? "Yes" : "No") << endl;
}

template<typename T> void pv(vector<T> vec) {
  cout << "[";
  for(auto& v : vec) { cout << v << ","; }
  cout << "]" << endl;
}

template<typename T> void pv2(vector<vector<T>> vec) {
  for(auto& v : vec) pv(v);
}

template<>
void pv(vector<P> vec) {
  cout << "[";
  for(auto& v : vec) {
    cout << "<" << v.fi << ","<< v.se << ">" << ",";
  }
  cout << "]" << endl;
}
int maze[50][50];
int ans;
void init(){
  rep(i,50)rep(j,50) maze[i][j] = 0;
  ans = 0;
}
int dx[8] = {1,1,0,-1,-1,-1,0,1};
int dy[8] = {0,1,1,1,0,-1,-1,-1};
void ume(int i,int j) {
  maze[i][j] = 0;
  rep(k,8) {
    int nx = i+dx[k];int ny = j+dy[k];
    if(isin(nx,0,50) and isin(ny,0,50) and maze[nx][ny]) ume(nx,ny);
  }
  return;
}
vi ansvec;
int main() {
  while(true){

  int w,h;
  cin >> w >> h;
  if(w==0 and h == 0) {
    for(auto v : ansvec) cout << v << endl;
    return 0;
  }
  init();
  rep(i,h) rep(j,w) cin >> maze[i][j];
  rep(i,h) rep(j,w) {
    if(maze[i][j] == 1) {
      ume(i,j);
      ans++;
    }
  }
  ansvec.eb(ans);
}
  return 0;
}

C++: #include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>
#include <fstream>

using namespace std;
#define REP(i, n) for (int (i) = 0; (i) < (n); (i)++)
#define FOR(i, a, b) for (int (i) = (a); (i) < (b); (i)++)
#define RREP(i, a) for(int (i) = (a) - 1; (i) >= 0; (i)--)
#define FORR(i, a, b) for(int (i) = (a) - 1; (i) >= (b); (i)--)
#define DEBUG(C) cerr << #C << " = " << C << endl;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<LL>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using PII = pair<int, int>;
using PDD = pair<double, double>;
using PLL = pair<LL, LL>;
using VPII = vector<PII>;
#define ALL(a) begin((a)), end((a))
#define RALL(a) rbegin((a)), rend((a))
#define SORT(a) sort(ALL((a)))
#define RSORT(a) sort(RALL((a)))
#define REVERSE(a) reverse(ALL((a)))
#define MP make_pair
#define FORE(a, b) for (auto &&a : (b))
#define FIND(s, e) ((s).find(e) != (s).end())
#define EB emplace_back

const int INF = 1e9;
const int MOD = INF + 7;
const LL LLINF = 1e18;

VVI C;
vector<vector<bool>> used;
int MH, MW;
int dh[] = {0, 0, -1, 1, -1, -1, 1, 1};
int dw[] = {-1, 1, 0, 0, -1, 1, -1, 1};
bool inside(int h, int w) {
    return 0 <= h && h < MH && 0 <= w && w < MW;
}
bool dfs(int h, int w) {
    if (used[h][w]) return false;
    used[h][w] = true;
    REP(i, 8) {
        int nh = h + dh[i], nw = w + dw[i];
        if (!inside(nh, nw)) continue;
        if (C[nh][nw] == 1) dfs(nh, nw);
    }
    return true;
}
void solve(int w, int h) {
    MH = h; MW = w;
    C.resize(h, VI(w));
    used.resize(h, vector<bool>(w, false));
    REP(i, h)REP(j, w) cin >> C[i][j];
    int cnt = 0;
    REP(i, h)REP(j, w) {
        if (C[i][j] == 1) cnt += dfs(i, j);
    }
    cout << cnt << endl;
    used.clear();
    C.clear();
    return;
}

int main(void) {
    int n, p, m, w, h;
    string s;
    int a, b, c;
    while (cin >> w >> h) {
        if (w == 0 && h == 0) return 0;
        solve(w, h);
        //return 0;
    }
}

C++: #include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<cassert>
#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<queue>
#include<set>
#include<map>
#include<utility>
#include<numeric>
#include<algorithm>
#include<bitset>
#include<complex>

using namespace std;

typedef long long Int;
typedef vector<int> vint;
typedef pair<int,int> pint;
#define mp make_pair

template<class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cout << *i << " "; cout << endl; }
template<class T> void chmin(T &t, T f) { if (t > f) t = f; }
template<class T> void chmax(T &t, T f) { if (t < f) t = f; }
int in() { int x; scanf("%d", &x); return x; }

int sea[60][60];
int w,h;

void f(int x,int y){
//cout<<x<<" "<<y<<endl;
	int i,j;
/*for(i=0;i<h;i++){
	for(j=0;j<w;j++){
		cout<<sea[i][j]<<" ";
	}
	cout<<endl;
}*/
	sea[y][x]=0;
	for(i=-1;i<2;i++){
		for(j=-1;j<2;j++){
			if(y+i<0||h<=y+i||x+j<0||w<=y+i)continue;
			if(sea[y+i][x+j]==1)f(x+j,y+i);
		}
	}
}

int main() {
	while(w=in(),h=in()){
		int i,j;
		for(i=0;i<h;i++){
			for(j=0;j<w;j++){
				cin>>sea[i][j];
			}
		}
		/*for(i=0;i<h;i++){
			for(j=0;j<w;j++){
				cout<<sea[i][j]<<" ";
			}
			cout<<endl;
		}*/
		int res=0;
		for(i=0;i<h;i++){
			for(j=0;j<w;j++){
				if(sea[i][j]==1){
					f(j,i);
					res++;
				}
			}
		}
		cout<<res<<endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define int long long
#define Rep(i, N) for(int i = 0; i < N; i++)

typedef pair<int, int> Pi;
#define fi first
#define se second

int mx[] = {1, 1, 0, -1, -1, -1, 0, 1};
int my[] = {0, 1, 1, 1, 0, -1, -1, -1};
int W, H;
int mas[55][55];

void bfs(int sy, int sx) {
  
  queue < Pi > que;
  que.push(Pi(sy, sx));

  while(!que.empty()) {
    Pi d = que.front(); que.pop();
    int y = d.fi, x = d.se;
    Rep(i, 8) {
      int ny = y + my[i], nx = x + mx[i];
      if(ny < 0 || nx < 0 || ny >= H || nx >= W || !mas[ny][nx]) continue;
      mas[ny][nx] = 0; bfs(ny, nx);
    }
  }
}

signed main()
{  
  while(cin >> W >> H, W || H) {
    int ans = 0;
    Rep(i, H) Rep(j, W) cin >> mas[i][j];

    Rep(i, H) Rep(j, W) {
      if(mas[i][j]) {
	mas[i][j] = 0, ans++;
	bfs(i, j);
      }
    }

    cout << ans << endl;
  }
}