#include using namespace std; typedef long long ll; typedef long double ld; typedef double db; typedef string str; typedef pair pi; typedef pair pl; typedef pair pd; typedef vector vi; typedef vector vl; typedef vector vd; typedef vector vs; typedef vector vpi; typedef vector vpl; typedef vector vpd; #define mp make_pair #define f first #define s second #define sz(x) (int)(x).size() #define all(x) begin(x), end(x) #define rall(x) (x).rbegin(), (x).rend() #define rsz resize #define ins insert #define ft front() #define bk back() #define pf push_front #define pb push_back #define eb emplace_back #define lb lower_bound #define ub upper_bound #define FOR(i,a,b) for (int i = (a); i < (b); ++i) #define F0R(i,a) FOR(i,0,a) #define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i) #define R0F(i,a) ROF(i,0,a) #define trav(a,x) for (auto& a: x) const int MOD = 1e9+7; // 998244353; const int MX = 2e5+5; const ll INF = 1e18; const ld PI = acos((ld)-1); const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; //mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); template bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; } template bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; } constexpr int pct(int x) { return __builtin_popcount(x); } constexpr int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down ll half(ll x) { return fdiv(x,2); } template T fstTrue(T lo, T hi, U f) { hi ++; assert(lo <= hi); // assuming f is increasing while (lo < hi) { // find first index such that f is true T mid = half(lo+hi); f(mid) ? hi = mid : lo = mid+1; } return lo; } template T lstTrue(T lo, T hi, U f) { lo --; assert(lo <= hi); // assuming f is decreasing while (lo < hi) { // find first index such that f is true T mid = half(lo+hi+1); f(mid) ? lo = mid : hi = mid-1; } return lo; } template void remDup(vector& v) { sort(all(v)); v.erase(unique(all(v)),end(v)); } // INPUT template void re(complex& c); template void re(pair& p); template void re(vector& v); template void re(array& a); template void re(T& x) { cin >> x; } void re(db& d) { str t; re(t); d = stod(t); } void re(ld& d) { str t; re(t); d = stold(t); } template void re(H& h, T&... t) { re(h); re(t...); } template void re(complex& c) { A a,b; re(a,b); c = {a,b}; } template void re(pair& p) { re(p.f,p.s); } template void re(vector& x) { trav(a,x) re(a); } template void re(array& x) { trav(a,x) re(a); } // TO_STRING #define ts to_string str ts(char c) { return str(1,c); } str ts(const char* s) { return (str)s; } str ts(str s) { return s; } str ts(bool b) { #ifdef LOCAL return b ? "true" : "false"; #else return ts((int)b); #endif } template str ts(complex c) { stringstream ss; ss << c; return ss.str(); } str ts(vector v) { str res = "{"; F0R(i,sz(v)) res += char('0'+v[i]); res += "}"; return res; } template str ts(bitset b) { str res = ""; F0R(i,SZ) res += char('0'+b[i]); return res; } template str ts(pair p); template str ts(T v) { // containers with begin(), end() #ifdef LOCAL bool fst = 1; str res = "{"; for (const auto& x: v) { if (!fst) res += ", "; fst = 0; res += ts(x); } res += "}"; return res; #else bool fst = 1; str res = ""; for (const auto& x: v) { if (!fst) res += " "; fst = 0; res += ts(x); } return res; #endif } template str ts(pair p) { #ifdef LOCAL return "("+ts(p.f)+", "+ts(p.s)+")"; #else return ts(p.f)+" "+ts(p.s); #endif } // OUTPUT template void pr(A x) { cout << ts(x); } template void pr(const H& h, const T&... t) { pr(h); pr(t...); } void ps() { pr("\n"); } // print w/ spaces template void ps(const H& h, const T&... t) { pr(h); if (sizeof...(t)) pr(" "); ps(t...); } // DEBUG void DBG() { cerr << "]" << endl; } template void DBG(H h, T... t) { cerr << ts(h); if (sizeof...(t)) cerr << ", "; DBG(t...); } // #define LOCAL #ifdef LOCAL // compile with -DLOCAL #define dbg(...) cerr << "LINE(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__) #else #define dbg(...) 0 #define assert(...) 0 #endif // FILE I/O void setIn(str s) { freopen(s.c_str(),"r",stdin); } void setOut(str s) { freopen(s.c_str(),"w",stdout); } void unsyncIO() { ios_base::sync_with_stdio(0); cin.tie(0); } void setIO(str s = "") { unsyncIO(); // cin.exceptions(cin.failbit); // throws exception when do smth illegal // ex. try to read letter into int if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO } int N; const int maxv = 102; int pre[maxv][maxv]; int val[maxv][maxv]; int main() { cin >> N; for (int i = 1; i <= N; i++) { for (int j = 1; j <= N; j++) { cin >> val[i][j]; pre[i][j] = val[i][j] + pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1]; } } int ans = INT_MIN; for (int i1 = 1; i1 <= N; i1++) { for (int j1 = 1; j1 <= N; j1++) { for (int i2 = i1; i2 <= N; i2++) { for (int j2 = j1; j2 <= N; j2++) { ans = max(ans, pre[i2][j2] - pre[i1 - 1][j2] - pre[i2][j1 - 1] + pre[i1 - 1][j1 - 1]); } } } } cout << ans; }