Uses crt;
const n=20;
var i,average,count:integer;
a:array[1..n] of integer;
begin
randomize;
writeln('Введите элементы массива:');
for i:=1 to n do
begin
read(a[i]);
if i mod 2<>0 then
begin
average:=average+a[i];
inc(count);
end;
end;
writeln(average DIV count);
end.