题解 | 杨辉三角的变形

n = int(input())
if n <= 2:
    print('-1')
else:
    out = '2324'
    print(out[(n-2)%4-1])

## 发现2324的循环
# n = int(input())
# if n <= 2:
#     print('-1')
# arr = [1]
# for hang in range(2,n):
#     # print(arr)
#     arr.insert(0,0)
#     arr.append(0)
#     tem_arr = [1 for _ in range(len(arr))]
#     for i in range(1,len(tem_arr)-1):
#         tem_arr[i] = arr[i-1] + arr[i] + arr[i+1]
#     arr = tem_arr
#     # print(arr)
#     for j in range(len(arr)):
#         if arr[j]%2 == 0 :
#             print(j+1)
#             break