def alternatingSum(L):
    return
 
    
def double(lst):
    return

    
def rangeSum(lo,hi):
    return


    



### Tests for alternatingSum ###
assert(alternatingSum([5,3,8,4]) == 6)
assert(alternatingSum([1,2,3,4]) == -2)
assert(alternatingSum([10,10,10,10]) == 0)
assert(alternatingSum([0]) == 0)