Definition: In this task, you're given a sentence and your task is to generate a simplified sentence that focuses on lexical paraphrasing from the original sentence given in the input.

Positive Example 1 -
Input: a georgian inscription around the drum attests his name.
Output: there is a georgian inscription around the drum to confirm his name.

Positive Example 2 -
Input: it is particularly famous for the cultivation of kiwifruit.
Output: it is mostly famous for the growing of kiwifruit.

Negative Example 1 -
Input: a hunting dog refers to any dog who assists humans in hunting.
Output: a hunting dog is a dog that refers humans in hunting.

Negative Example 2 -
Input: in return , romania ceded three southern districts of bessarabia to russia and acquired dobruja.
Output: in return , romania ceded three southern districts of bessarabia to russia and acquired dobruja.

Now complete the following example -
Input: natural ytterbium is a mix of seven stable isotopes.
Output: 



Output:
natural ytterbium is a combination of seven stable isotopes.
natural ytterbium is a mixture of seven stable isotopes.
ytterbium is made of seven isotopes.