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<iostream>
#include<vector>
#include<queue>
#include<tuple>
#include<set>
#include<climits>
#include<algorithm>
using namespace std;

const int INF = INT_MAX;

class Node {
public:
    int y, x, depth;
    Node(int y, int x, int d) :y(y), x(x), depth(d) {}
};

typedef tuple<int, int> Point;

enum {EVEN, ODD};
enum {Y, X};
const int NEXT[2][6][2] = {
    {
        {-1, -1},
        {-1, 0},
        {0, -1},
        {0, 1},
        {1, -1},
        {1, 0},
    },
    {
        {-1, 0},
        {-1, 1},
        {0, -1},
        {0, 1},
        {1, 0},
        {1, 1},
    },
};

int bfs(vector<vector<int>>& field, int y, int x, bool write) {
    int h = field.size(), w = field[0].size();
    int result = 0;
    set<Point> visited;
    queue<Node> q;
    q.push(Node(y, x, 0));
    while(!q.empty()) {
        Node current = q.front(); q.pop();
        if(visited.count(Point(current.y, current.x))) continue;
        visited.insert(Point(current.y, current.x));
        if(field[current.y][current.x] <= current.depth) continue;
        if(write) field[current.y][current.x] = current.depth;
        ++result;
        for(const auto& d: NEXT[y & 1]) {
            int ny = current.y + d[Y];
            int nx = current.x + d[X];
            if(ny < 0 || h <= ny) continue;
            if(nx < 0 || w <= nx) continue;
            q.push(Node(ny, nx, current.depth + 1));
        }
    }
    return result;
}

int main() {
    int m, n;
    int s, t;
    int x, y;
    while(cin >> m >> n, m | n) {
        vector<vector<int>> field(n, vector<int>(m, INF));
        for(cin >> s; s > 0; --s) {
            cin >> x >> y;
            bfs(field, y - 1, x - 1, true);
        }
        int answer = 0;
        for(cin >> t; t > 0; --t) {
            cin >> x >> y;
            answer = max(answer, bfs(field, y - 1, x - 1, false));
        }
        cout << answer << endl;
    }
}

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

using namespace std;

#define FOR(i,k,n) for(int i=(k); i<(int)(n); ++i)
#define REP(i,n) FOR(i,0,n)
#define FORIT(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)

template<class T> void debug(T begin, T end){ for(T i = begin; i != end; ++i) cerr<<*i<<" "; cerr<<endl; }
inline bool valid(int x, int y, int W, int H){ return (x >= 0 && y >= 0 && x < W && y < H); }

typedef long long ll;
const int INF = 100000000;
const double EPS = 1e-8;
const int MOD = 1000000007;
int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
typedef pair<int, int> P;
void bfs(int sx, int sy, int d[111][111]){
  const int W = 110;
  const int H = 110;
  REP(y, H) REP(x, W) d[y][x] = INF;
  queue<int> qx, qy;
  qx.push(sx); qy.push(sy);
  d[sy][sx] = 0;
  while(!qx.empty()){
    int x = qx.front(); qx.pop();
    int y = qy.front(); qy.pop();
    if(y % 2 == 1){
      int dx[6] = {-1, 0, 1, 0, -1, -1};
      int dy[6] = {-1, -1, 0, 1, 1, 0};
      REP(r, 6) {
        int nx = x + dx[r];
        int ny = y + dy[r];
        if(valid(nx, ny, W, H) && d[ny][nx] > d[y][x] + 1){
          d[ny][nx] = d[y][x] + 1;
          qx.push(nx); qy.push(ny);
        }
      }
    }else{
      int dx[6] = {0, 1, 1, 1, 0, -1};
      int dy[6] = {-1, -1, 0, 1, 1, 0};
      REP(r, 6) {
        int nx = x + dx[r];
        int ny = y + dy[r];
        if(valid(nx, ny, W, H) && d[ny][nx] > d[y][x] + 1){
          d[ny][nx] = d[y][x] + 1;
          qx.push(nx); qy.push(ny);
        }
      }
    }
  }
}

int main(){
  int W, H;
  while(cin >> W >> H && W){
    int N;
    int tx[10], ty[10];
    cin >> N;
    REP(i, N) cin >> tx[i] >> ty[i];
    int dist[11][111][111];
    REP(i, N){
      bfs(tx[i], ty[i], dist[i]);
    }
    int ans = 0;
    int M; cin >> M;
    REP(i, M){
      int nx, ny; cin >> nx >> ny;
      bfs(nx, ny, dist[N]);
      int cnt = 0;
      REP(y, H)REP(x, W){
        //printf("nx = %d ny = %d x = %d y = %d dist %d\n", nx, ny, x + 1, y + 1, dist[N][y + 1][x + 1]);
        bool ok = true;
        REP(j, N) if(dist[N][y + 1][x + 1] >= dist[j][y + 1][x + 1]) ok = false;
        if(ok) cnt++;
      }
      ans = max(ans, cnt);
    }
    cout << ans << endl;
  }
  return 0;
}