It shows that x+Y must not be decomposed into two prime numbers, 1 excluding: 5, 7, 8, 9, 10, 12, 13, 14, 15,/kloc.

40,42,46,48,52.

Remaining: 6, 1 1, 17, 23, 37, 29, 33, 35, 37, 38, 39, 4 1, 43, 44, 45, 47, 49.

B said, "I know what X and Y are!" "

Explain that there is only one way for x*y, which is decomposed and in the rest of the above example.

6:2*4=8

1 1:2*9= 18、3*8=24、4*7=28、5*6=30

17:2* 15=30、3* 14=42、4* 13=52、5* 12=60、6* 1 1=66、7* 10=70、8*9=72

23:2*2 1=42、3*20=60~~~~~

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I don't write forms anymore. I use c++, which is programmed to type ~ ~ ~ ~ ~ ~ ~

Here 30, 42, 60 and so on appear many times.

Because they are multiples of 6=2*3, multiples that are multiples of two prime numbers like this are often divided into more than one group.

So it is impossible for B to get such a number (the sum of two numbers here must be satisfied at the same time, so it is not necessarily excluded)

What meets the requirements here is that

A, b

6, 8 (but 8 can only have 2*4, B can know from the beginning, A won't say you don't know)

1 1, 18

1 1,24

17,52

23,76

23, 1 12

27,50

27,92

29,54

29, 168

35,304 (but 304 = 16 * 19 = 8 * 38 = 4 * 76 = 2 *152, and only16 *19 with x and y within 30.

37,232 (but 304 = 8 * 29 = 4 * 58 = 2 *116, where x and y are within 30, only 8 * 29, so the reason for exclusion is the same as 8).

A said, "I know, too."

Explain that the number of A can only have the unique number of B..

Only17,52 pairs 413 ~ ~ ~ ~

1 & lt； X<y & lt30 is only 4, 13.