inp = open('inp.txt','r+')
out = open('out.txt','w+')
g = 9.81
h = inp.read()
H = h.split()
for i in range (len(H)) :
    H[i] = int(H[i])
V = (2*g*H)**0.5
v = str(V)
out.write(v)
inp.close()
out.close()