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

local a, b, k = io.read("*n", "*n", "*n")
a = 1LL * a
b = 1LL * b
local gcd = getgcd(a, b)
local lcm = (a / gcd) * b

local min, max = 0LL, 1000000000LL * 1000000001LL
while 1LL < max - min do
  local mid = (min + max) / 2LL
  local v = mid / a + mid / b - mid / lcm
  if k <= v then
    max = mid
  else
    min = mid
  end
end
max = tostring(max):gsub("LL", "")
print(max)