# 看了大佬的思路，重点还是找规律啊
# 看了大佬的思路，重点还是找规律啊
while 1:
    try:
        n = int(input())
        g = [2,3,2,4]
        if n<3:
            print(-1)
        else:
            print(g[(n-2)%4-1])
    except:
        break