#!/usr/bin/env python3

# TLE: does not sort the list and insted recomputes for each interesting framerate.
n, m = [int(i) for i in input().split()]
xs = [int(i) for i in input().split()]
# local minimum is whenever s(f) jumps or at f=M

# first do f = M
optt = 0
for x in xs:
    if (m * x) % 1000 == 0:
        optt += (m * x) // 1000
    else:
        optt += 1 + (m * x) // 1000
optt /= m

# now all other interesting points
fs = {}
for x in xs:
    maxv = (m * x) // 1000
    for i in range(1, maxv + 1):
        # DO NOT enumerate in sorted order -> TLE
        # recalculate frames each time
        t = 0
        for y in xs:
            # f = 1000i/xi
            # fs = fy/1000 = iy/xi
            if (i * y) % x == 0:
                t += (i * y) // x
            else:
                t += 1 + (i * y) // x
        t /= (1000 * i) / x
        if t < optt:
            optt = t
print(optt)