var
a:array [1..100,1..100]of integer;
n,i,j, Summ:integer;
begin
write ('n = ');
readln(n);
for i:=1 to n do
begin
for j:=1 to n do
begin
a[i,j]:= random (99);
write ( a[i,j]:4);
end;
writeln;
end;
Summ := 0;
for i := 1 to (n div 2 + n mod 2) do
for j := i to n - i + 1 do
Summ := Summ + a[i,j];
writeln('Summ = ', Summ);
readln;
end.