def jumpIt(n, k, lst):
    sums = []
    #sums will collect the 'cost' of the game in a list
    if (k > n-1):
        #first base case if the list if the length is 0
        return 0
    elif (k+1 > n-1):
        #2nd base case if the list is two cells
        return lst[k]
    else:
        if (lst[k] < lst[k+1]):
            sums.append(lst[k])
            #if the cell of K is less than k+1 computes:
            return lst[k] + jumpIt(n, k+2, lst)
        else:
            sums.append(lst[k+1])
            return lst[k+1] + jumpIt(n, k+2, lst)



def main():
    #list to sum the cost of each move
    fileName = "input.txt"
    for line in open(fileName):
        lst = line.split()
        lst = [int(x) for x in lst]
        print(jumpIt(len(lst),1,lst))

main()

19
87
138
186
330

19
85
108
157
224