93 Choose two different numbers from $\{19,20,21, \cdots, 91,92,93\}$, so that their sum is even. The total number of ways to do this is $\qquad$.
931369 . Among the natural numbers from 19 to 93, there are 38 odd numbers and 37 even numbers. The sum of the two selected numbers is even if and only if the two numbers have the same parity. Therefore, the total number of ways to select is
$$
C_{38}^{2}+C_{37}^{2}=1369 \text { (ways). }
$$