No Odd Sum

There are $N$ numbers written on a blackboard. The $i$-th number is denoted as $A_i$. The blackboard is said to be *good* if, for each pair of indices $(i, j)$ with $1 \leq i \lt j \leq N$, the sum $(A_i + A_j)$ is an even number. The blackboard might not be *good* initially, so you want to make it *good*. To do this, you can perform the following two types of operations: 1. Erase a $2$ from