/*************************************
* author: marvinthang *
* created: 18.01.2024 23:36:31 *
*************************************/
#include "soccer.h"
#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define left ___left
#define right ___right
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define MASK(i) (1LL << (i))
#define BIT(x, i) ((x) >> (i) & 1)
#define __builtin_popcount __builtin_popcountll
#define ALL(v) (v).begin(), (v).end()
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define REPD(i, n) for (int i = (n); i-- > 0; )
#define FOR(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define FORD(i, b, a) for (int i = (b), _a = (a); --i >= _a; )
#define FORE(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORDE(i, b, a) for (int i = (b), _a = (a); i >= _a; --i)
#define scan_op(...) istream & operator >> (istream &in, __VA_ARGS__ &u)
#define print_op(...) ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
#include "debug.h"
#else
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define DB(...) 23
#define db(...) 23
#define debug(...) 23
#endif
template <class U, class V> scan_op(pair <U, V>) { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>) { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>) { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")"; else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
// copied from https://codeforces.com/blog/entry/76149
template<typename T, int D> struct Vec: public vector <Vec <T, D - 1>> {
static_assert(D >= 1, "Vector dimension must be greater than zero!");
template <typename... Args>
Vec(int n = 0, Args... args): vector <Vec <T, D - 1>>(n, Vec <T, D - 1>(args...)) {}
};
template<typename T> struct Vec <T, 1>: public vector <T> {
Vec(int n = 0, const T& val = T()): vector <T>(n, val) {}
};
template <class A, class B> bool minimize(A &a, B b) { return a > b ? a = b, true : false; }
template <class A, class B> bool maximize(A &a, B b) { return a < b ? a = b, true : false; }
// end of template
const int INF = 1e9;
int biggest_stadium(int N, vector <vector <int>> F) {
if (N <= 30) {
Vec <int, 4> dp(N, N, N, N + 1, -INF);
Vec <int, 2> pref(N, N + 1);
REP(i, N) partial_sum(ALL(F[i]), pref[i].begin() + 1);
REP(i, N) REP(r, N + 1) REP(l, r)
if (pref[i][l] == pref[i][r]) dp[i][i][l][r] = r - l;
int res = 0;
REP(x2, N) REPD(x1, x2 + 1) REP(r, N + 1) REP(l, r) if (dp[x1][x2][l][r] >= 0) {
maximize(res, dp[x1][x2][l][r]);
FOR(l2, l, r) FORE(r2, l2 + 1, r) {
if (x1 && pref[x1 - 1][l2] == pref[x1 - 1][r2]) maximize(dp[x1 - 1][x2][l2][r2], dp[x1][x2][l][r] + r2 - l2);
if (x2 + 1 < N && pref[x2 + 1][l2] == pref[x2 + 1][r2]) maximize(dp[x1][x2 + 1][l2][r2], dp[x1][x2][l][r] + r2 - l2);
}
}
return res;
}
vector <int> left(N), right(N);
REP(x, N) {
while (left[x] < N && F[x][left[x]]) ++left[x];
right[x] = left[x];
while (right[x] < N && !F[x][right[x]]) ++right[x];
FOR(i, right[x], N) if (!F[x][i]) return 0;
}
int l = 0;
while (left[l] == N) ++l;
int r = l;
while (r < N && left[r] < N) ++r;
FOR(i, r, N) if (left[i] < N) return 0;
--r;
int last = -1;
while (l <= r) {
int p = -1;
if (left[l] <= left[r] && right[r] <= right[l]) p = r;
else if (left[r] <= left[l] && right[l] <= right[r]) p = l;
if (p == -1) return 0;
if (last == -1 || (left[p] <= left[last] && right[last] <= right[p])) {
last = p;
if (p == l) ++l;
else --r;
} else return 0;
}
int cnt = 0;
REP(i, N) REP(j, N) cnt += !F[i][j];
return cnt;
}
