uses crt;
const
n=20
var
a:array [1..n] of integer;
i:integer;
sr:real;
begin 
randomize;
for i:=1 to n do 
a[i]:=random(40)-20;
sr:=0;
for i:=1 to n do begin
if a[i]>0 then sr:=sr+a[i];
end;
sr:=sqrt(sr);
writeln ('srednee geometricheskoe ravno',sr);
readln 
end.