num_list = list(map(int, (input().split())))
num_list.sort()

A = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

dif_list = []
for num, a in zip(num_list, A): #リストの各要素同士を引く
    dif = a - num
    dif_list.append(dif)
dif_list.index(-1)
print(dif_list.index(-1)+1)