You will be given a context and a verb separated with a newline character, and you have to answer if the given verb is a negation or not. A verb is a negation if it is not going to exist, not happen, or has no effect. The output should be "Yes" if the verb is a negation and "No" otherwise.

Let me give you an example: Only the government of the United States can decide if it prefers this variant, continued the letter, which Castro read on a state television station broadcast. Gonzalez for months refused requests by Elian's Miami relatives to go to the United States to (claim) the boy.  
 Verb: claim
The answer to this example can be: Yes
Here is why: This is a good example. Gonzalez refused to "claim" the boy. So, the claim didn't happen and it's a negation.

OK. solve this:
Now the alliance's mission is more ill-defined. NATO warplanes (helped) end the war in Bosnia almost four years ago and now are poised to intervene in Yugoslavia should peace efforts in the province of Kosovo fail.  
 Verb: helped
Answer:
No