local function lltonumber(str)
  local ret = 0LL
  for i = 1, #str do
    ret = ret * 10LL
    ret = ret + tonumber(str:sub(i, i))
  end
  return ret
end

local function getgcd(x, y)
  while 0 < x do
    x, y = y % x, x
  end
  return y
end
local s = io.read()
local st, sa, sb = s:match("(%d+) (%d+) (%d+)")
local t, a, b = lltonumber(st), lltonumber(sa), lltonumber(sb)
local ra = (t - 1LL) / a + 1
local rb = (t - 1LL) / 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)