#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 510;
short ly[N][N][N], ry[N][N][N];
bool a[N][N];
int s[N][N], dp[N][N][N], m;
int biggest_stadium(int n, vector<vector<int>> f) {
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
a[i][j] = f[i - 1][j - 1];
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
s[i][j] = s[i][j - 1] + a[i][j];
for (int i = 1; i <= n; i++)
for (int l = 1; l <= n; l++)
for (int r = l; r <= n; r++)
ly[i][l][r] = ry[i][l][r] = -1;
for (int l = 1; l <= n; l++)
for (int r = n; r >= l; r--) {
int ptr = 1;
while (ptr <= n) {
if (s[ptr][r] - s[ptr][l - 1] > 0) {
ptr++;
continue;
}
int last = ptr;
while (last <= n && s[last][r] - s[last][l - 1] == 0)
last++;
for (int i = ptr; i < last; i++) {
ly[i][l][r] = ptr;
ry[i][l][r] = last - 1;
}
ptr = last;
}
}
int ans = 0;
for (int i = 1; i <= n; i++)
for (int l = 1; l <= n; l++)
for (int r = n; r >= 1; r--)
if (ly[i][l][r] >= 0) {
int u = ly[i][l][r];
int v = ry[i][l][r];
dp[i][l][r] = max(dp[i][l][r], (v - u + 1) * (r - l + 1));
ans = max(ans, dp[i][l][r]);
if (l < r) {
int nu = ly[i][l + 1][r];
int nv = ry[i][l + 1][r];
dp[i][l + 1][r] = max(dp[i][l + 1][r], dp[i][l][r] + (nv - v + u - nu) * (r - l));
nu = ly[i][l][r - 1];
nv = ry[i][l][r - 1];
dp[i][l][r - 1] = max(dp[i][l][r - 1], dp[i][l][r] + (nv - v + u - nu) * (r - l));
}
}
return ans;
}
/*
int main()
{
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);
return 0;
}
//*/
