const
handsfree = false;
nmax = 10;
random_min = -50;
random_max = 50;
var
a: array[0..nmax] of real;
i, n: integer;
sum, x: real;
begin
{ввод массива}
n := nmax;
if handsfree then begin
for i := 0 to n do
begin
a[i] := random(random_max - random_min) + random_min;
write(a[i], ' ');
end
end
else begin
for i := 0 to n do
readln(a[i]);
end;
writeln();
{подсчет суммы}
write('x = ');
readln(x);
sum := a[n];
for i := n - 1 downto 0 do
sum := sum * x + a[i];
writeln('S = ', sqrt(sum));
end.
using namespace std;
int main() {
int k=0, sum=0;
cin >> k;
for(int i=14;i<k;i++) {
sum += i;
}
cout << sum << endl;
system("Pause");
return 0;
}