with open("input", "r") as input:
    input = list(map(int, input.read().strip().split(",")))
    fuel = []

    for i in range(min(input), max(input)):
        total_fuel = 0
        for x in input:
            for y in range(1, abs(i - x) + 1):
                total_fuel += y
        fuel.append(total_fuel)

    fuel.sort()
    print(fuel[0])