var s:array[0..101,0..101]of longint；

f:array[0..101]of longint；

n,i,j,k,t,max,oo:longint；

begin

max:=-1000000；

readln(n)；

for i:=1 to n do

for j:=1 to n do

begin

read(oo)；

s[i,j]:=s[i-1,j]+s[i,j-1]-s[i-1,j-1]+oo；

end；

for k:=1 to n do

for i:=1 to n-k+1 do

begin

t:=0；

for j:=1 to n do

begin

f[j]:=f[j-1]+s[i+k-1,j]-s[i+k-1,j-1]-s[i-1,j]+s[i-1,j-1]；

if f[j]-f[t]>max then max:=f[j]-f[t]；

if f[j]-f[t]<=0 then t:=j；

end；

end；

if max<0 then max:=0；

writeln(max)；

end.

program p106;

var i,j,k,n,max,now:longint;

e:array[0..100,0..100]of longint;

begin

readln(n);

for i:=1 to n do

for j:=1 to n do

begin

read(k);

e[i,j]:=e[i-1,j] + e[i,j-1] - e[i-1,j-1]+k;

end;

max:=-100000;

for k:=1 to n do

begin

now:=0;

for i:=1 to n-k+1 do

for j:=1 to n do

begin

inc(now,e[i+k-1,j]-e[i+k-1,j-1]-e[i-1,j]+e[i-1,j-1]);

if now>max then max:=now;

if now<=0 then

now:=0;

end;

end;

if max<0 then writeln(0)

else writeln(max);

end.