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 <cstdio>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
using namespace std;

struct UnionFind {
        int n;
        vector<int> parent;
        vector<int> rank;
        vector<int> num;
        int find(int x) {
                if (parent[x] == x) return  x;
                return parent[x] = find(parent[x]);
        }
        UnionFind(int n_) {
                n = n_;
                parent.resize(n);
                for (int i = 0; i < n; i ++) parent[i] = i;
                rank.assign(n, 0);
                num.assign(n, 1);
        }
        void unite(int x, int y) {
                if ((x = find(x)) != (y = find(y))) {
                        if (rank[x] < rank[y]) {
                                parent[x] = y;
                                num[y] += num[x];
                        } else {
                                parent[y] = x;
                                if (rank[x] == rank[y]) rank[x] ++;
                                num[x] += num[y];
                        }
                        n --;
                }
        }
        bool same(int x, int y) { return find(x) == find(y); }
        int get() { return n; }
        int get(int x) { return num[find(x)]; }
};

int main() {
        int w, h;
        while (scanf("%d%d", &w, &h), w) {
                vector<vector<int>> s(h, vector<int> (w));
                int lands = 0;
                map<pair<int, int>, int> ptol;
                for (int i = 0; i < h; i ++) {
                        for (int j = 0; j < w; j ++){
                                scanf("%d", &s[i][j]);
                                if (s[i][j]) {
                                        ptol[make_pair(i, j)] = lands;
                                        lands ++;
                                }
                        }
                }
                UnionFind uf(lands);
                auto get = [&](int a, int b) { return ptol[make_pair(a, b)]; };
                for (int i = 0; i < h; i ++) {
                        for (int j = 0; j < w; j ++) {
                                if (s[i][j]) {
                                        if (i - 1 >= 0 && j + 1 < w && s[i - 1][j + 1]) uf.unite(get(i, j), get(i - 1, j + 1));
                                        if (j + 1 < w && s[i][j + 1])                   uf.unite(get(i, j), get(i, j + 1));
                                        if (i + 1 < h && j + 1 < w && s[i + 1][j + 1])  uf.unite(get(i, j), get(i + 1, j + 1));
                                        if (i + 1 < h && s[i + 1][j])                   uf.unite(get(i, j), get(i + 1, j));
                                }
                        }
                }
                printf("%d\n", uf.get());
        }
        return 0;
}

C++: #include <iostream>
#define UMI 0
#define RIKU 1
using namespace std;

int w,h;
int c[50][50];

void pr(){
  for( int i=0;i<h;i++ ){
    for( int j=0;j<w;j++ )
      cout << c[i][j] << " ";
    cout << endl;
  }
}

void check( int x,int y){
  if( x<0 || x>=h ) return;
  if( y<0 || y>=w ) return;
  if( c[x][y]==UMI ) return;

  c[x][y] = UMI;
  check( x-1, y-1);
  check( x-1, y  );
  check( x-1, y+1);
  check( x  , y-1);
  check( x  , y+1);
  check( x+1, y-1);
  check( x+1, y  );
  check( x+1, y+1);
}

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 << w <<" "<< h<<endl;
    //    pr();
    int sum = 0;
    for( int i=0;i<h;i++ )
      for( int j=0;j<w;j++ )
	if( c[i][j]==RIKU ){
	  ++sum;
	  check(i,j);
	}
    cout << sum << endl;
  }

  return 0;
}

C++: #include <cstdio>
#include <cstring>

char map[51][51];
int res;
int w,h;

int dfs(int sx, int sy) {
    if(sx<0 || sx>w-1 || sy<0 || sy>h-1) return 0;
    if(map[sy][sx] == '0') return 0;

    map[sy][sx] = '0';

    dfs(sx+1,sy);
    dfs(sx,sy+1);
    dfs(sx-1,sy);
    dfs(sx,sy-1);
    dfs(sx+1,sy+1);
    dfs(sx+1,sy-1);
    dfs(sx-1,sy+1);
    dfs(sx-1,sy-1);
    return 1;
}

int main(void)
{
    int px,py;

    while(true)
    {
        res = 0;
        scanf("%d%d", &w, &h);
        if(!w && !h) break;
        for(int j=0; j < h; j++)
        for(int i=0; i < w; i++)
            scanf("%s", &map[j][i]);

        for(int j=0; j < h; j++)
        for(int i=0; i < w; i++)
            res += dfs(i, j);

        printf("%d\n", res);
    }

    return 0;
}