One

uses Compl;

const n = 5;

var a: array[1..n,1..n] of complex;
    i, j, k, m: integer;
    S1,S2,S: complex;

begin
    Zero(S);
    k := 0;
    for i := 1 to n do
    begin
      for j := 1 to n do
      begin
        a[i,j].Re  :=  random(4) + 1;
        a[i,j].Im  :=  random(4) + 1;
        write(a[i,j].Re, '.', a[i,j].Im);
        write('  ')
      end;
      writeln;
    end;
    writeln;

    m := trunc((n+1)/2);

    for i := 1 to n do
      for j := 1 to m do
      begin
        Add(S,a[i,j],S);
        inc(k);
      end;


    Prod(1/k,S,S);
    Output(S);
    writeln
end.