const kmax = 101;
var n, n2, k, t, i, j: byte;
    a: array[1..kmax] of byte;
begin
     read(k);
     for i := 1 to k do
         read(a[i]);
     for i := 1 to k - 1 do
         for j := 1 to k - i do
             if a[j] > a[j + 1] then begin
                t := a[j];
                a[j] := a[j + 1];
                a[j + 1] := t;
             end;
     n := 0;
     for i := 1 to k div 2 + 1 do
         inc(n, a[i] div 2 + 1);
     write(n);
end.