It can be known from the following formula: m = a = 3a/3, n = (a+2)/3, and p = (2a+ 1)/3.

Then the size of comparison m, n and p is the size of comparison 3A, A+2, 2A+ 1.

3a-(a+2)=2a-2

2a-3 >； because a> 1; 0,3a & gtA+2, that is, M> ordinary

a+2-(2a+ 1)= 1-a & lt； 0, so a+2

3a-(2a+ 1)= a- 1 & gt； 0, so 3a & gt2a+ 1, that is, m >；; p，

To sum up: M>P> is ordinary.