summax.cpp

#include<iostream>
#include<vector>
#include<map>

#define long long long
#define nln '\n'

using namespace std;

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    freopen("summax.inp", "r", stdin);
    freopen("summax.ans.out", "w", stdout);
    long n;
    cin >> n;
    vector<vector<long>> a(n);
    for (long i = 0; i < n; ++i){
        a[i].resize(n, 0);
        for (long j = 0; j < n; ++j)
            cin >> a[i][j];
    }
    map<long, long> sum;
    for (long i = 0; i < n; ++i)
        for (long j = 0; j < n; ++j)
            sum[i-j] += a[i][j];

    long res = LLONG_MIN;
    for (auto i : sum)
        res = (i.second > res) ? i.second : res;
    cout << res << nln;
    return 0;
}