local n, m = io.read("*n", "*n")
local t = {}
for i = 1, n do
  t[i] = 0
end
for i = 1, m do
  local z = i
  while z <= n do
    t[z] = t[z] - i
    z = z + i
  end
end
t[1] = m - 1
for i = 2, n do
  t[i] = m + t[i] + t[i - 1]
end
local a = 0
for i = 1, n do
  a = math.max(a, t[i])
end
print(a)