古典问题：有一对兔子，从出生后第3个月起每个月都生一对兔子，小兔子长到第三个月

　　　后每个月又生一对兔子，假如兔子都不死，问每个月的兔子总数为多少？-Classical problem: a pair of rabbits from the three month after the birth of every month at a pair of rabbits, a small rabbit is long to the first three months

After a month gave birth to a rabbit if the rabbit is not dead, and asked each month of the rabbit is the total number?