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Logic 2 help
Take into consideration that each of the men can make assumptions based on the action of the other two men. Any of the men can notice something according to how the other men react.
Man 1 sees both of the other two mens' hats. Man 2 can see the hat of the one man in front of him. Man 3 can see none of the hats.
Obviously Man 3 is of no help to the others. But…think.
I am trying not to give too much information away.