import math, strscans

var (_, a, b) = stdin.readLine.scanTuple("$f $f")

# f(x) = (x-a)(x-b)
# x^3/3 -ax^2/2 -bx^2/2 +abx

proc fn(x: float): auto =
  x ^ 3 / 3 - a * x ^ 2 / 2 - b * x ^ 2 / 2 + a * b * x 

echo a.fn - b.fn