#include <bits/stdc++.h>
using namespace std;
template<typename T>
int SIZE(T (&t)){
    return t.size();
}

template<typename T, size_t N>
int SIZE(T (&t)[N]){
    return N;
}

string to_string(char t){
    return "'" + string({t}) + "'";
}

string to_string(bool t){
    return t ? "true" : "false";
}

string to_string(const string &t, int x1=0, int x2=1e9){
    string ret = "";
    for(int i = min(x1,SIZE(t)), _i = min(x2,SIZE(t)-1); i <= _i; ++i){
        ret += t[i];
    }
    return '"' + ret + '"';
}

string to_string(const char* t){
    string ret(t);
    return to_string(ret);
}

template<size_t N>
string to_string(const bitset<N> &t, int x1=0, int x2=1e9){
    string ret = "";
    for(int i = min(x1,SIZE(t)); i <= min(x2,SIZE(t)-1); ++i){
        ret += t[i] + '0';
    }
    return to_string(ret);
}

template<typename T, typename... Coords>
string to_string(const T (&t), int x1=0, int x2=1e9, Coords... C);

template<typename T, typename S>
string to_string(const pair<T, S> &t){
    return "(" + to_string(t.first) + ", " + to_string(t.second) + ")";
}

template<typename T, typename... Coords>
string to_string(const T (&t), int x1, int x2, Coords... C){
    string ret = "[";
    x1 = min(x1, SIZE(t));
    auto e = begin(t);
    advance(e,x1);
    for(int i = x1, _i = min(x2,SIZE(t)-1); i <= _i; ++i){
        ret += to_string(*e, C...) + (i != _i ? ", " : "");
        e = next(e);
    }
    return ret + "]";
}

template<int Index, typename... Ts>
struct print_tuple{
    string operator() (const tuple<Ts...>& t) {
        string ret = print_tuple<Index - 1, Ts...>{}(t);
        ret += (Index ? ", " : "");
        return ret + to_string(get<Index>(t));
    }
};

template<typename... Ts>
struct print_tuple<0, Ts...> {
    string operator() (const tuple<Ts...>& t) {
        return to_string(get<0>(t));
    }
};

template<typename... Ts>
string to_string(const tuple<Ts...>& t) {
    const auto Size = tuple_size<tuple<Ts...>>::value;
    return print_tuple<Size - 1, Ts...>{}(t);
}

void dbgr(){;}
template<typename Heads, typename... Tails>
void dbgr(Heads H, Tails... T){
    cout << to_string(H) << " | ";
    dbgr(T...);
}

void dbgs(){;}
template<typename Heads, typename... Tails>
void dbgs(Heads H, Tails... T){
    cout << H << " ";
    dbgs(T...);
}

/*
formatted functions:
*/

/*
consider __VA_ARGS__ as a whole:
dbgv() prints values only
dbg() prints name and values
*/
#define dbgv(...) cout << to_string(__VA_ARGS__) << endl;

#define dbg(...) cout << "[" << #__VA_ARGS__ << "]: "; dbgv(__VA_ARGS__);
//#define dbg(...)

/*
consider __VA_ARGS__ as a sequence of arguments:
dbgr() prints values only
dbgm() prints names and values
*/
#define dbgr(...) dbgr(__VA_ARGS__); cout << endl;

#define dbgm(...) cout << "[" << #__VA_ARGS__ << "]: "; dbgr(__VA_ARGS__);

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

typedef long long ll;
typedef unsigned int ui;
typedef unsigned long long ull;
typedef pair<int, int> pi;
typedef pair<ll, ll> pll;
// using u128 = __uint128_t;
// using i128 = __int128;
const int mod = 1000000007;
const int N = 2005;
const int LOG = 20;
const int inf = 1e9;
const double eps = 1e-11;
int n, m, k, qq;
int a[N][N], up[N][N], dp[N][N], nxt[N][N];
int prefr[N][N], pref[N][N];
int queryp(int rx, int ry) {
    return (rx < 0 || ry < 0 ? 0 : pref[rx][ry]);
}

int query(int lx, int rx, int ly, int ry) {
    return queryp(rx, ry) - queryp(lx - 1, ry) - queryp(rx, ly - 1) + queryp(lx - 1, ly - 1);
}

pi findup(int rx, int ly, int ry) {
    int l = 0, r = rx, lx = -1;
    while (l <= r) {
        int mid = (l + r) / 2;
        if (query(mid, rx, ly, ry)) l = mid + 1;
        else r = mid - 1, lx = mid;
    }
    
    if (lx == 0 || a[lx - 1][ly]) return {lx, ly};
    else return {lx, nxt[lx - 1][ly]};
}

int dfs(int i, int j) {
    if (i == n) return -inf;
    if (dp[i][j] != -1) return dp[i][j];
    int lx = findup(i, j, j).first, rx = i;
    int l = 0, r = j, ly = -1, ry = -1;
    while (l <= r) {
        int mid = (l + r) / 2;
        if (query(lx, rx, mid, j)) l = mid + 1;
        else r = mid - 1, ly = mid;
    }
    
    l = j, r = n - 1;
    while (l <= r) {
        int mid = (l + r) / 2;
        if (query(lx, rx, j, mid)) r = mid - 1;
        else l = mid + 1, ry = mid;
    }
    
    if (query(lx, rx, ly, ry)) return -inf;
    if (lx == 0 && j > ly) return dp[i][j] = dp[i][ly];
    else {
        int pp = (a[lx - 1][ly] ? ly : nxt[lx - 1][ly]);
        if (pp < j) return dp[i][j] = dp[i][pp];  
    }
    
    int szx = rx - lx + 1, szy = ry - ly + 1, cntx = 0;
    dp[i][j] = szx * szy;
    if (lx != 0) {
        int pl = ly, cur = min(ry + 1, (a[lx - 1][ly] ? ly : nxt[lx - 1][ly]));
        while (true) {
            cntx++;
            if (pl < cur) {
                auto [lxx, p] = findup(rx, pl, cur - 1);
                dp[i][j] = max(dp[i][j], dfs(i, p) + szx * (szy - cur + pl));
            }
            
            if (cur == ry + 1) break;
            pl = cur + 1, cur = min(ry + 1, nxt[lx - 1][cur]);
        }
    }
    
    if (rx != n - 1) {
        int pl = ly, cur = min(ry + 1, (a[rx + 1][ly] ? ly : nxt[rx + 1][ly]));
        while (true) {
            cntx++;
            if (pl < cur) {
                auto [lxx, p] = findup(rx + 1, pl, cur - 1);
                dp[i][j] = max(dp[i][j], dfs(i + 1, p) + szx * (szy - cur + pl));
            }
            
            if (cur == ry + 1) break;
            pl = cur + 1, cur = min(ry + 1, nxt[rx + 1][cur]);
        }
    }
    
    return dp[i][j];
}

int biggest_stadium(int NN, std::vector<std::vector<int>> F) {
    n = NN;
    memset(dp, -1, sizeof(dp));
    for (int i = 0; i < n; i++) nxt[i][n] = n;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            a[i][j] = F[i][j];
            prefr[i][j] = (j == 0 ? 0 : prefr[i][j - 1]) + a[i][j];
            pref[i][j] = (i == 0 ? 0 : pref[i - 1][j]) + prefr[i][j];
        }
        
        for (int j = n - 1; j >= 0; j--) {
            nxt[i][j] = nxt[i][j + 1];
            if (a[i][j + 1]) nxt[i][j] = j + 1;
        }
    }
    
    int out = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (a[i][j]) continue;
            out = max(out, dfs(i, j));
        }
    }
    
    return out;
}

// void solve() {
//     int N;
//     assert(1 == scanf("%d", &N));
//     std::vector<std::vector<int>> F(N, std::vector<int>(N));
//     for (int i = 0; i < N; i++)
//     {
//         for (int j = 0; j < N; j++)
//         {
//             assert(1 == scanf("%d", &F[i][j]));
//         }
//     }
//     fclose(stdin);

//     int res = biggest_stadium(N, F);

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


// int32_t main() {
//     std::ios::sync_with_stdio(false);
//     cin.tie(NULL);
//     solve();
// }