1. Compute the sum:

$$
\sqrt{2020-\sqrt{2021 \cdot 2019}}+\sqrt{2018-\sqrt{2019 \cdot 2017}}+\cdots+\sqrt{2-\sqrt{3 \cdot 1}}
$$
Answer: $\frac{\sqrt{2021}-1}{\sqrt{2}}$.

Solution: a similar solution to this problem is present in Variant 1 under the same number.