Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
	)

var scanner = bufio.NewScanner(os.Stdin)

const INF = 0x7FFFFFFF

var (
	direction1 = [][]int{ // 奇数段目の移動方向
		{-1, 0}, {1, 0}, {0, -1}, {0, 1}, {1, -1}, {1, 1},
	}
	direction2 = [][]int{ // 偶数段目の移動方向
		{-1, -1}, {0, -1}, {1, 0}, {0, 1}, {-1, 1}, {-1, 0},
	}
)

func main() {
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		m, _ := strconv.Atoi(buf[0])
		n, _ := strconv.Atoi(buf[1])
		if m == 0 && n == 0 {
			break
		}
		// initialize district_map
		/*
			district_map = [
				[-1, -1,  -1,  -1,  -1]
				[-1, INF, INF, INF, -1]
				[-1, INF, INF, INF, -1]
				[-1, INF, INF, INF, -1]
				[-1, INF, INF, INF, -1]
				[-1, -1,  -1,  -1,  -1]
			]
		*/
		district_map := make([][]int, n+2)
		for i := range district_map {
			district_map[i] = make([]int, m+2)
		}
		tmp1 := make([]int, m+2)
		for i := range tmp1 {
			tmp1[i] = -1
		}
		district_map[0] = tmp1
		district_map[n+1] = tmp1
		for i := 1; i < n+1; i++ {
			district_map[i] = make([]int, m+2)
			district_map[i][0] = -1
			district_map[i][m+1] = -1
			for j := 1; j < m+1; j++ {
				district_map[i][j] = INF
			}
		}

		scanner.Scan()
		s, _ := strconv.Atoi(scanner.Text())
		for i := 0; i < s; i++ {
			scanner.Scan()
			buf_ := strings.Split(scanner.Text(), " ")
			x, _ := strconv.Atoi(buf_[0])
			y, _ := strconv.Atoi(buf_[1])
			Search(Point{x, y}, district_map, m, n)
		}
		ans := 0
		scanner.Scan()
		t, _ := strconv.Atoi(scanner.Text())
		for i := 0; i < t; i++ {
			scanner.Scan()
			buf__ := strings.Split(scanner.Text(), " ")
			x, _ := strconv.Atoi(buf__[0])
			y, _ := strconv.Atoi(buf__[1])
			z := Count(Point{x, y}, district_map, m, n)
			ans = max(ans, z)
		}
		fmt.Println(ans)
	}
}

func max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

type Point struct {
	x, y int
}

type Entry struct {
	hop   int
	point Point
}

func Search(p Point, mp [][]int, m, n int) {
	que := make([]Entry, 0)
	que = append(que, Entry{0, p})
	check := make([][]bool, n+2)
	for i := range check {
		check[i] = make([]bool, m+2)
	}
	check[p.y][p.x] = true
	mp[p.y][p.x] = 0
	var direction [][]int
	for len(que) > 0 {
		tmp := que[0]
		que = que[1:]
		dist, point := tmp.hop, tmp.point
		if point.y%2 == 0 {
			direction = direction1
		} else {
			direction = direction2
		}
		for _, d := range direction {
			nx, ny := point.x+d[0], point.y+d[1]
			if !check[ny][nx] && mp[ny][nx] != -1 {
				check[ny][nx] = true
				if mp[ny][nx] > dist+1 {
					mp[ny][nx] = dist + 1
				}
				que = append(que, Entry{dist + 1, Point{nx, ny}})
			}
		}
	}
}

func Count(p Point, mp [][]int, m, n int) int {
	que := make([]Entry, 0)
	que = append(que, Entry{0, p})
	check := make([][]bool, n+2)
	for i := range check {
		check[i] = make([]bool, m+2)
	}
	check[p.y][p.x] = true
	ans := 1
	var direction [][]int
	for len(que) > 0 {
		tmp := que[0]
		que = que[1:]
		dist, point := tmp.hop, tmp.point
		if point.y%2 == 0 {
			direction = direction1
		} else {
			direction = direction2
		}
		for _, d := range direction {
			nx, ny := point.x+d[0], point.y+d[1]
			if !check[ny][nx] && mp[ny][nx] != -1 {
				check[ny][nx] = true
				if mp[ny][nx] > dist+1 {
					ans++
				}
				que = append(que, Entry{dist + 1, Point{nx, ny}})
			}
		}
	}
	return ans
}

C++: #include <bits/stdc++.h>
using namespace std;

const int dx[7] = {0, 0, -1, -1, 0, 1, 1};
const int dy[2][7] = {
	{0, -1, -1, 0, 1, 0, -1},
	{0, -1, 0, 1, 1, 1, 0}
};

int n, m;
int g[200][200];
int grid[200][200];
int grid2[200][200];

bool ok(int i, int j)
{
	return i >= 0 && j >= 0 && i < n && j < m;
}

int solve()
{
	int maxi = 0;
	memcpy(grid, g, sizeof(g));
	for (int a = 0; a < 200; a++){
		memset(grid2, 0, sizeof(grid2));
		for (int i = 0; i < n; i++){
			for (int j = 0; j < m; j++){
				for (int dir = 0; dir < 7; dir++){
					int nx = i + dx[dir];
					int ny = j + dy[i % 2][dir];
					if (!ok(nx, ny)) continue;
					grid2[nx][ny] |= grid[i][j];
				}
			}
		}
		
		int cnt = 0;
		for (int i = 0; i < n; i++){
			for (int j = 0; j < m; j++){
				if (grid2[i][j] == (grid2[i][j] & (-grid2[i][j]))){
					grid[i][j] = grid2[i][j];
					if (grid[i][j] == 1) cnt++;
				}
				//printf("%d ", grid[i][j]);
			}
			//puts("");
		}
		maxi = max(maxi, cnt);
	}
	return maxi;
}

int main()
{
	while (scanf("%d %d", &m, &n), m){
		memset(g, 0, sizeof(g));
		int maxi = 0;
		int s;
		scanf("%d", &s);
		for (int i = 0; i < s; i++){
			int x, y;
			scanf("%d %d", &x, &y);
			g[--y][--x] = 1 << i + 1;
		}
		int t;
		scanf("%d", &t);
		for (int i = 0; i < t; i++){
			int p, q;
			scanf("%d %d", &p, &q);
			if (g[--q][--p]) continue;
			g[q][p] = 1;
			maxi = max(maxi, solve());
			g[q][p] = 0;
		}
		printf("%d\n", maxi);
	}
	
	return 0;
}

C++: #include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
using namespace std;

typedef istringstream ISS;
typedef ostringstream OSS;
typedef vector<string> VS;
typedef int INT;
typedef vector<INT> VI;
typedef vector<VI> VVI;
typedef pair <INT, INT> II;
typedef vector <II> VII;

template<class T> ostream& operator << ( ostream& os, vector<T> v ) {
    for ( typename vector<T>::iterator it_i = v.begin(); it_i != v.end(); ++it_i ) {
        os << *it_i << ", ";
    }
    return os;
}


const int SIZE = 11;
const int MSIZE = 101;

int w, h;
int s;
int X[SIZE], Y[SIZE];
int t;
int PT[SIZE], QT[SIZE];
int T[MSIZE][MSIZE];
int Tcopy[MSIZE][MSIZE]; 

const int DSIZE = 6;
const int dr[2][DSIZE] = {
    { 1, 1, 0, 0, -1, -1 },
    { 1, 1, 0, 0, -1, -1 }
};
const int dc[2][DSIZE] = {
    { -1, 0, -1, 1, -1, 0 },
    { 0, 1, -1, 1, 0, 1 }
};

void init() {
    for ( int i = 0; i < MSIZE; ++ i ) {
        for ( int j = 0; j < MSIZE; ++ j ) {
            T[i][j] = INT_MAX;
        }
    }
}

void save() {
    for ( int i = 0; i < MSIZE; ++ i ) {
        for ( int j = 0; j < MSIZE; ++ j ) {
            Tcopy[i][j] = T[i][j];
        }
    }
}

void load() {
    for ( int i = 0; i < MSIZE; ++ i ) {
        for ( int j = 0; j < MSIZE; ++ j ) {
            T[i][j] = Tcopy[i][j];
        }
    }
}

typedef II NODE;
typedef queue <NODE> QUEUE;

bool isValidPos( int r, int c ) {
    return r >= 0 && r < h && c >= 0 && c < w;
}

int spread( int sr, int sc ) {
    QUEUE Q;
    Q.push( II( sr, sc ) );
    T[sr][sc] = 0;
    
    int res = 1;
    while ( ! Q.empty() ) {
        NODE node = Q.front();
        Q.pop();

        int r = node.first;
        int c = node.second;
        int d = r % 2;

        for ( int i = 0; i < DSIZE; ++ i ) {
            int nr = r + dr[d][i];
            int nc = c + dc[d][i];
            if ( ! isValidPos( nr, nc ) ) continue;
            if ( T[r][c] + 1 >= T[nr][nc] ) continue;
            T[nr][nc] = T[r][c] + 1;
            res ++;
            NODE next( nr, nc );
            Q.push( next );
        }
    }
    return res;
}

void solve() {
    init();
    for ( int i = 0; i < s; ++ i ) {
        spread( Y[i], X[i] );
    }
    save();
    int res = 0;
    for ( int i = 0; i < t; ++ i ) {
        load();
        res = max( res, spread( QT[i], PT[i] ) );
    }
    cout << res << endl;
    return;
}

void input() {
    cin >> s;
    for ( int i = 0; i < s; ++ i ) {
        cin >> X[i] >> Y[i];
        X[i] -= 1;
        Y[i] -= 1;
    }
    cin >> t;
    for ( int i = 0; i < t; ++ i ) {
        cin >> PT[i] >> QT[i];
        PT[i] -= 1;
        QT[i] -= 1;
    }
}

int main() {
    while ( cin >> w >> h ) {
        if ( w == 0 && h == 0 ) break;
        input();
        solve();
    }
    return 0;
}