题解 | #杨辉三角的变形#

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