N = int(input())

if N == 4:
    print("3")
elif N == 6:
    print("5")
elif N in [8,9,10,15,16,22]:
    print("7")
elif N == 12:
    print("11")
elif N == 14:
    print("13")
elif N in [20,21]:
    print("19")
elif N in [24,25]:
    print("23")
elif (N-1) % 8 != 0:
    print("8")
elif int((N-1) / 8) % 10 in [1,2,4,5,7,9]:
    print("8")
else:
    idx = int((N-1) / 8)+1

    if idx in [7,9]:
        print(int((N-1)/2))
    else:
        print(N-2)