n, s, b = io.read("*n", "*n", "*n")
h = {}
for i = 1, n do
  h[i] = io.read("*n")
end
local z = h[1] + s * b
for i = 2, n do
  if z < h[i] then
    print("No") os.exit()
  end
  z = math.max(z, h[i] + s * b)
end
print("Yes")