题解 | #杨辉三角的变形#

while True:
    try:
        n = int(input())
        if n > 2 and n % 2 == 0:
            if n % 4 == 0:
                print(3)
            else:
                print(4)
        elif n > 2 and n % 2 == 1:
            print(2)
        else:
            print(-1)
    except:
        break