type TFile = file of real;
var f, g: TFile;
mul, tmp: real;
i, n: integer;
begin
randomize;
AssignFile(f, '000');
AssignFile(g, '111');
rewrite(f);
readln(n);
for i := 1 to n do
begin
tmp := random(20);
write(f, tmp);
end;
CloseFile(f);
rewrite(g);
reset(f);
mul := 1;
while not eof(f) do
begin
read(f, tmp);
mul := mul*tmp
end;
write(g, mul);
CloseFile(f);
CloseFile(g);
write(mul:5:3);
readln
end.