题解 | #杨辉三角的变形#

while True:
try:
n = int(input())
matrix = [[0 for i in range(2 * n - 1)] for _ in range(n)]
# for line in matrix:
# print(line)
# print()
matrix[0][len(matrix[0]) // 2] = 1
matrix[1][len(matrix[0]) // 2] = 1
matrix[1][len(matrix[0]) // 2 - 1] = 1
matrix[1][len(matrix[0]) // 2 + 1] = 1

    for i in range(2, len(matrix)):
        # print(i)
        for j in range(len(matrix[0])):
            # 左
            if 0 <= j - 1 <= len(matrix[0]) - 1:
                left = matrix[i - 1][j - 1]
            else:
                left = 0

            # 中
            if 0 <= j <= len(matrix[0]) - 1:
                mid = matrix[i - 1][j]
            else:
                mid = 0

            # 右
            if 0 <= j + 1 <= len(matrix[0]) - 1:
                right = matrix[i - 1][j + 1]
            else:
                right = 0

            matrix[i][j] = left + mid + right
    # for line in matrix:
    #     print(line)

    exist = False
    for i in range(len(matrix[-1])):
        if matrix[-1][i] != 0 and matrix[-1][i] % 2 == 0:
            print(i + 1)
            exist = True
            break
    if not exist:
        print(-1)


except:
    break