a, b, c = map(int, input().split(" "))
a = int(a)
b = int(b)
c = int(c)
lst = [a, b, c]
lst.sort()
d = lst[0]-lst[1]*lst[2]
e = lst[0]-lst[1]-lst[2]
if d<e:
    min = d
else:
    min = e
print(min)