local function getgcd(x, y)
  while 0 < x do
    x, y = y % x, x
  end
  return y
end

local t = 0LL + io.read("*n")
local a = 0LL + io.read("*n")
local b = 0LL + io.read("*n")

local ra = (t - 1) / a + 1
local rb = (t - 1) / b + 1
local gcd = getgcd(a, b)

local rc = ((t - 1) / a) / (b / gcd) + 1

local str = tostring(ra + rb - rc):gsub("LL", "")
print(str)