A, B, C = map(int, input().split())

def solve(A, B, C):
    if A == B or B == C or C == A or sorted([A, B, C])[1] not in [A, C]:
        print(0)
    elif B == max([A, B, C]):
        print(B - max(A, C))
    elif B == min([A, B, C]):
        print(min(A, C) - B)
    else:
        print(0)

solve(A, B, C)