输入同学的人数n计算出其生日不重复的概率。 然后在用彷真的方法, 利用随机数产生每个同学的生日，计算出生日不重复的概率并与前面的结果进行比较-N Enter the number of students to calculate the probability of non-repetition of their birthday. And then use the simulation method, using random number generator for each stude