Var
a: Array[1..30,1..30] of Integer;
n,p, i,j: Integer;
BEGIN
writeln('n=');
readln(n);
Writeln('vvedite massiv:');
For i:=1 to n do
begin
For j:=1 to n do
begin
read(a[i,j]);
end;
Writeln;
end;
p:=1;
for j:=1 to n do
if (a[3,j]>0)
then
p:=p*a[3,j];
writeln('p=',p);
readln;
end.