Definition: 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.

Positive Example 1 -
Input: 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
Output: Yes

Positive Example 2 -
Input: In Washington today, the Federal Aviation Administration (released) air traffic control tapes from the night the TWA Flight eight hundred went down.  
 Verb: released
Output: No

Negative Example 1 -
Input: WASHINGTON ( AP ) -- Preliminary DNA tests link a missing anti-abortion activist to a strand of hair found near where a sniper shot and killed a Buffalo, N.Y., doctor who (performed) abortions, a law enforcement official said Friday.  
 Verb: performed
Output: Yes

Negative Example 2 -
Input: He insisted that the NGO law " will not change our position at all ". " We won't (refuse) foreign donations, nor will we register as a 'foreign agent', " he said.  
 Verb: refuse
Output: No

Now complete the following example -
Input: It was unclear if American authorities would give the Cubans the 28 visas they have proposed. The group would not (leave) until Gonzalez had assurances that American authorities would give him custody of his son.  
 Verb: leave
Output: 


Answer: Yes