// $Id: heapsort.ici,v 1.0 2003/01/03 12:19:00 dada Exp $
// http://dada.perl.it/shootout
//
// contributed by Tim Long

static IM = 139968;
static IA = 3877;
static IC = 29573;

static
gen_random(max)
{
    static last = 42;

    return max * (last = (last * IA + IC) % IM) / IM ;
}

static
heapsort(n, ra)
{
    ir = n;
    l = (n >> 1) + 1;
    for (;;)
    {
        if (l > 1)
        {
            rra = ra[--l];
        }
        else
        {
            rra = ra[ir];
            ra[ir] = ra[1];
            if (--ir == 1)
            {
                ra[1] = rra;
                return;
            }
        }
        i = l;
        j = l << 1;
        while (j <= ir)
        {
            if (j < ir && ra[j] < ra[j+1])
                ++j;
            if (rra < ra[j])
            {
                ra[i] = ra[j];
                j += (i = j);
            }
            else
            {
                j = ir + 1;
            }
        }
        ra[i] = rra;
    }
}

N = argv[1] ? int(argv[1]) : 1;
ary = array();
for (i = 0; i <= N; ++i)
    ary[i] = gen_random(1.0);
heapsort(N, ary);
printf("%.10f\n", ary[N]);