Var
   A:array[1..30,1..30] of real;
   N,k,O,i,j:integer;
   P:real;
Begin
Write('N = ');
ReadLn(N);
WriteLn('Ââåäèòå ìàòðèöó âåùåñòâåííûõ ÷èñåë A(',N,',',N,'):');
For i:= 1 to N do
    For j:= 1 to N do
        Read(A[i,j]);
WriteLn;
k:=0;
P:=1;
O:=N div 2+N mod 2+1;
For i:= O to N-1 do
    For j:= O to N do
        if j < i then
           if A[i,j] < 0 then
              Begin
              k:=k+1;
              P:=P*A[i,j]
              End;
if k=0 then WriteLn('Èñêîìûõ ýëåìåíòîâ íåò')
else WriteLn('P = ',P);
ReadLn
End.