var a:array[1..100] of integer;
n,i,d:byte;
t:real;
begin
d:=0
repeat
readln(n);
until (0<n) and (n<=20);
for i:=1 to n do
readln(a[i]);
for i:=1 to n do
begin
d:=d+a[i];
end;
tb:=d/n;
writeln('trung binh cong cac phan tu trong day la',tb:0:2);
readln;
end.
~~~~~~~~~~~GOOD LUCK~~~~~~~~~~~~