def print_corner_matrix(n): """ 打印 n x n 的拐角方阵 """ for i in range(1, n + 1): row_values = [] for j in range(1, n + 1): # 核心逻辑：取行号和列号的最小值 val = min(i, j) row_values.append(str(val)) # 使用空格连接每行的数字并输出 print(" ".join(row_values)) if __name__ == "__main__": try: # 读取输入 n = int(input()) # 验证输入范围 (1 <= n <= 20) if 1 <= n <= 20: print_corner_matrix(n) except ValueError: pass