type
    Stroke = array of real;
var
    n : integer;
    x, y : Stroke;
    xs, ys, op1, op2, r: real;

procedure InputStroke(var a: Stroke; n: integer);
var
    i : integer;
begin
    write('Ввод массива: ');
    SetLength(a, n);
    for i := Low(a) to High(a) do
        read(a[i]);
end;

function AverageSum(const a: Stroke): real;
var
    S : real := 0;
    i : integer;
    n : integer := 0;
begin
    for i := Low(a) to High(a) do begin
        S := S + a[i];
        inc(n)
    end;
    AverageSum := S / n;
end;

function FirstOperand(const x, y: Stroke; xs, ys: real): real;
var
    S : real := 0;
    i : integer;
begin
    for i := Low(x) to High(x) do
        S := S + (x[i] - xs)*(y[i] - ys);
    FirstOperand := S;
end;

function SecondOperand(const x, y: Stroke; xs, ys: real): real;
var
    S1 : real := 0;
    S2 : real := 0;
    i: integer;
begin
    S1 := FirstOperand(x, x, xs, xs);
    S2 := FirstOperand(y, y, ys, ys);
    SecondOperand := S1 * S2;
end;

begin
    write('Введите количество элементов массива x и y:');
    readln(n);
    InputStroke(x, n);
    InputStroke(y, n);
    xs := AverageSum(x);
    ys := AverageSum(y);
    op1 := FirstOperand(x,y,xs,ys);
    op2 := SecondOperand(x,y,xs,ys);
    r := op1/op2;
    writeln('Для проверки вычислений:');
    writeln('xs=',xs);
    writeln('ys=', ys);
    writeln('Делимое=', op1);
    writeln('Делитель=', op2);
    writeln('Коэффициент корреляции двух величин R=', r);
end.