//2.100

Begin
  var aw: array[1..20] of real;
  var n, i: integer;
  var sum: real;
  
  sum := 0;
  
  write('Vvedite kol-vo elementov: ');
  readln(n);
  
  for i := 1 to n do
  begin
    write('Vvedite AW(',i,'): ');
    readln(AW[i]);
    
    if (i mod 2) = 0 then
      sum := sum + AW[i];
  end;
  
  writeln('Summa elementov = ', sum);
End.