l, r, c = io.read("*n", "*n", "*n")
r = math.min(r, l + 1000)
ans = 999LL
for i = l, r do
  z = (1LL * i * c) % 1000LL
  z = 1000LL - z
  if z == 1000LL then z = 0LL end
  if z < ans then ans = z end
end
ans = tostring(ans):gsub("LL", "")
print(ans)