请用多层感知器（MLP）神经网络误差反向传播（BP）算法实现异或问题（输入为，要求可以判别输出为0或1），并画出学习曲线。其中，非线性函数采用S型Logistic函数。-Please use the Multilayer Perceptron (MLP) back propagation neural network (BP) algorithm XOR problem (input is required to determine the output is 0 or 1), and draw the learning curve. Among them, the non-linear function using S-type Logistic functions.