Which is the correct translation of "Two rivers cannot flow into each other."

Question

• $R(x)$ - "x is a river"
• $L(x)$ - "x is a lake"
• $S(x)$ - "x is a sea"
• $F(x, y)$ - "x flows into y"

The domain consists only of waterbodies (rivers, lakes and seas).

"Two rivers cannot flow into each other."

(1) $ \forall x \forall y (R(x) \wedge R(y) \rightarrow \neg F(x, y) \wedge \neg F(y, x))$
(2) $ \forall x \forall y (R(x) \wedge R(y) \rightarrow \neg (F(x, y) \wedge F(y, x)))$

I believe the answer to be number 1, but number 2 is proposed to be the correct answer.

Is the natural language sentence ambiguous and can be translated in either way?

Answer 1

To me, "two rivers cannot flow into each other" means that river A could flow into river B, or river B could flow into river A, but not both. That is what the symbolic expression (2) means. The symbolic expression (1) means that no river can flow into another (A cannot flow into B, and B cannot flow into A).