str = gets.split
q = str[0].to_i
c = str[1].to_i
ps = [2, 3, 5, 7, 11, 13]
cs = [4, 6, 8, 9, 10, 12]
pps = Hash.new(0)
ccs = Hash.new(0)
qc = ps.length ** q
cc = cs.length ** c
if qc > 1
    qc.times do |i|
        bin = i.to_s(6)
        w = 1
        q.times do |j|
            if j < bin.length
                w *= ps[bin[j].to_i]
            else
                w *= ps[0]
            end
        end
        pps[w] += 1
    end
else
    pps[1] = 1
end
if cc > 1
    cc.times do |i|
        bin = i.to_s(6)
        w = 1
        c.times do |j|
            if j < bin.length
                w *= cs[bin[j].to_i]
            else
                w *= cs[0]
            end
        end
        ccs[w] += 1
    end
else
    ccs[1] = 1
end
m = Hash.new(0)
pps.each do |k1, v1|
    ccs.each do |k2, v2|
        m[k1 * k2] += v1 * v2;
    end
end
sum = 0
m.each do |k, v|
    sum += k * v
end
puts sum.to_f / (qc * cc)