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 <bits/stdc++.h>
using namespace std;

int fill_land(int y,int x,int h,int w,vector<vector<int>> &c);

int main()
{

	for (;;)
	{
		int w,h;
		cin >> w >> h;
		if ((w==0)&&(h==0))
		{
			return 0;
		}

		vector<vector<int>> c(h,vector<int>(w));

		for (int i=0;i<h;++i)
		{
			for (int j=0;j<w;++j)
			{
				cin >> c[i][j];
			}
		}

		int count=0;
		for (int i=0;i<h;++i)
		{
			for (int j=0;j<w;++j)
			{
				if (c[i][j]!=0)
				{
					// land
					++count;
					c[i][j]=0;
					fill_land(i,j,h,w,c);
				}
			}
		}
		cout << count << endl;
	}
}

int fill_land(int y,int x,int h,int w,vector<vector<int>> &c)
{
	stack<pair<int,int>> st;

	st.push(make_pair(y,x));
	while (st.empty()==0)
	{
		auto p=st.top();
		st.pop();

		if ( (p.first>0) && (c[p.first-1][p.second]!=0) )
		{
			c[p.first-1][p.second]=0;
			st.push(make_pair(p.first-1,p.second));
		}
		if ( (p.first<h-1) && (c[p.first+1][p.second]!=0) )
		{
			c[p.first+1][p.second]=0;
			st.push(make_pair(p.first+1,p.second));
		}
		if ( (p.second>0) && (c[p.first][p.second-1]!=0) )
		{
			c[p.first][p.second-1]=0;
			st.push(make_pair(p.first,p.second-1));
		}
		if ( (p.second<w-1) && (c[p.first][p.second+1]!=0) )
		{
			c[p.first][p.second+1]=0;
			st.push(make_pair(p.first,p.second+1));
		}
		if ( (p.first>0) && (p.second>0) && (c[p.first-1][p.second-1]!=0) )
		{
			c[p.first-1][p.second-1]=0;
			st.push(make_pair(p.first-1,p.second-1));
		}
		if ( (p.first>0) && (p.second<w-1) && (c[p.first-1][p.second+1]!=0) )
		{
			c[p.first-1][p.second+1]=0;
			st.push(make_pair(p.first-1,p.second+1));
		}
		if ( (p.first<h-1) && (p.second>0) && (c[p.first+1][p.second-1]!=0) )
		{
			c[p.first+1][p.second-1]=0;
			st.push(make_pair(p.first+1,p.second-1));
		}
		if ( (p.first<h-1) && (p.second<w-1) && (c[p.first+1][p.second+1]!=0) )
		{
			c[p.first+1][p.second+1]=0;
			st.push(make_pair(p.first+1,p.second+1));
		}
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;
int c[100][100];
int w, h;
void dfs(int x,int y) {
	c[x][y] = 0;
	for (int i = -1; i <= 1; i++) {
		for (int j = -1; j <= 1; j++) {
			if (x + i < w&&x + i >= 0 && y + j >= 0 && y + j < h) {
				if (c[x + i][y + j] == 1) {
					dfs(x + i, y + j);
				}
			}
		}
	}
}

int main(void) {
	int ans;
	while (1) {
		ans = 0;
		cin >> w >> h;
		if (w == 0 && h == 0) {
			break;
		}
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				cin >> c[j][i];
			}
		}
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				if (c[j][i] == 1) {
					dfs(j, i);
					ans++;
				}
			}
		}
		cout << ans << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <map>
#include <set>
using namespace std;

void add_label(map<int,int> &tbl, int a, int b){
	if( a == b ) return;
	if( a > b ) tbl[a] = b;
	else tbl[b] = a;
}

int main(void){
	int w, h;
	while( cin>>w>>h, w||h ) {
		vector<vector<int> > field( h );
		vector<vector<int> > labeled( h );
		for( int i=0; i<h; ++i ) {
			field[i] = vector<int>( w );
			labeled[i] = vector<int>( w );
			for( int j=0; j<w; ++j ) {
				cin>>field[i][j];
				labeled[i][j] = 0;
			}
		}
		int label = 1;
		map<int, int> tbl;
		for( int i=0; i<h; ++i ) {
			for( int j=0; j<w; ++j ) {
				if( field[i][j] ){
					bool f = false;
					if( i ) {
						if( j && labeled[i-1][j-1] ) {
							if(!f) labeled[i][j] = labeled[i-1][j-1];
							f = true;
						}
						if( labeled[i-1][j] ) {
							if(!f) labeled[i][j] = labeled[i-1][j];
							else add_label( tbl, labeled[i][j] ,labeled[i-1][j] );
							f = true;
						}
						if( j < w - 1 && labeled[i-1][j+1] ) {
							if(!f) labeled[i][j] = labeled[i-1][j+1];
							else add_label( tbl, labeled[i][j] ,labeled[i-1][j+1] );
							f = true;
						}
						if( j && labeled[i][j-1] ) {
							if(!f) labeled[i][j] = labeled[i][j-1];
							else add_label( tbl, labeled[i][j] ,labeled[i][j-1] );
							f = true;
						}
						if(!f) labeled[i][j] = ++label;
					} else {
						if( j && labeled[i][j-1] ){
							if(!f) labeled[i][j] = labeled[i][j-1];
							else add_label( tbl, labeled[i][j] ,labeled[i][j-1] );
							f = true;
						}
						if(!f) labeled[i][j] = ++label;
					}
				}
			}
		}
		for( auto x : tbl ) {
			int a = x.first;
			int b = x.second;
			while( tbl.find(b) != tbl.end() ) {
				b = tbl.find(b)->second;
			}
			for( int i=0; i<h; ++i ) {
				for( int j=0; j<w; ++j ) {
					if( labeled[i][j] == a ) labeled[i][j] = b;
				}
			}
		}
		
		for( int i=0; i<h; ++i ) {
			cerr<<"!";
			for( int j=0; j<w; ++j ) {
				cerr<<labeled[i][j];
			}
			cerr<<endl;
		}
		
		set<int> nums;
		nums.insert(0);
		for( int i=0; i<h; ++i ) {
			for( int j=0; j<w; ++j ) {
				nums.insert( labeled[i][j] );
			}
		}
		cout<<nums.size()-1<<endl;
	}
	return 0;
}