#!/usr/bin/env python3
#@EXPECTED_RESULTS@: RUN_TIME_ERROR, WRONG_ANSWER

# WA: Does not consider that the optimum can be not at an integer jump, but at the end of the interval.
# RE: As array of interesting times can be empty.
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

# WA: DO NOT do f = M

# now all other interesting points
fs = {}
for x in xs:
    maxv = (m * x) // 1000
    for i in range(1, maxv + 1):
        f = (i * 1000) / x
        if not f in fs:
            fs[f] = 1
        else:
            fs[f] += 1

# enumerate in sorted order
# with arbitrary low framerate each level takes 1 frame
sf = n
ts = []
for f in sorted(fs):
    t = sf / f
    ts.append(t)
    sf += fs[f]
# RE: empty minimum
print(min(ts))