n = int(input()) for k in range(1, 2 * n): # 计算数字行的长度 m 和前导空格数 spaces if k <= n: m = 2 * k - 1 spaces = n - k else: m = 2 * (2 * n - k) - 1 spaces = k - n # 生成数字部分 c = (m + 1) // 2 increasing = ''.join(str(i) for i in range(1, c + 1)) # 递增部分 decreasing = ''.join(str(i) for i in range(c - 1, 0, -1)) # 递减部分 line = increasing + decreasing # 打印带有前导空格的行 print(' ' * spaces + line)