尝试将两个以字符串形式输入数字的矩阵相加，然后显示解决方案，但使用stdin和stdout会遇到麻烦

def str_to_matrix(matrix_str):
    rows = matrix_str.strip().split('\n')
    matrix = []
    for row in rows:
        nums = row.strip().split()
        nums = [int(num) for num in nums]
        matrix.append(nums)
    return matrix

def add_matrices(matrix1, matrix2):
    result = []
    for i in range(len(matrix1)):
        row = []
        for j in range(len(matrix1[i])):
            row.append(matrix1[i][j] + matrix2[i][j])
        result.append(row)
    return result

# 主程序
matrix1_str = input("请输入第一个矩阵：")
matrix2_str = input("请输入第二个矩阵：")

matrix1 = str_to_matrix(matrix1_str)
matrix2 = str_to_matrix(matrix2_str)

result = add_matrices(matrix1, matrix2)

print("相加结果：")
for row in result:
    print(' '.join(str(num) for num in row))