a, b, c = list(map(int, input().split()))


pa = a / (a + b + c)
pb = b / (a + b + c)
pc = c / (a + b + c)
pab = (a + b) / (a + b + c)
pbc = (b + c) / (a + b + c)
pca = (c + a) / (a + b + c)


print(max(pa, pb, pc, pab, pbc, pca))