编写一个简单的Python程序，用于计算一个5×5矩阵的行列式。
矩阵内容参考：[[1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15], [16, 17, 18, 19, 20], [21, 22, 23, 24, 25]]
```python
matrix = [[1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15], [16, 17, 18, 19, 20], [21, 22, 23, 24, 25]]

def det(matrix):
    if len(matrix) == 2:
        return matrix[0][0]*matrix[1][1] - matrix[0][1]*matrix[1][0]
    elif len(matrix) > 2:
        determinant = 0
        for i in range(len(matrix)):
            copy = matrix[1:]
            for j in range(len(copy)):
                copy[j] = copy[j][0:i]+copy[j][i+1:]
            sign = (-1)**(i%2)
            cofactor = det(copy)
            determinant += sign*matrix[0][i]*cofactor
        return determinant

print(det(matrix)) # 输出结果为0
```

注意这个矩阵的行列式结果是0。