How to respond to "hey" from a guy?

Long story short, last night at my mates 21st there was this super cute guy. We conversed for a few minutes, but thats it. Today I added him on facebook and he messaged me saying "hey"! How the hell do i reply to that hahah
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+1 y
hmm alright :)
How to respond to "hey" from a guy?
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