def sum(f: Int => Int, a: Int, b: Int): Int =
  if (a > b)
    0
  else
    f(a) + sum(f, a + 1, b)

def id(x: Int): Int = x
def sumInts(a: Int, b: Int): Int = sum(id, a, b)

def kvadrId(x: Int): Int = x * x
def kvadr(a: Int, b: Int): Int = sum(kvadrId, a, b)

println(kvadr(0, 10))