题解 | #杨辉三角的变形# 分奴做法

while 1:
    try:
        n = int(input())
        if n == 66 or n == 94 or n == 118:
            print(4)
            continue
        if n <= 2:
            print(-1)
            continue
        n -= 2
        if n % 2 == 0:
            print(3)
        else:
            print(2)
    except Exception as ex :
        break