main :: IO ()
main = do
  l1 <- getLine
  l2 <- getLine
  let a = map read $ words l2 :: [Integer]
  print $ f 1 a

f y [] = if y > 10^18 then -1 else y
f y (x:xs) = if y > 10^18 then (if 0 `elem` xs then 0 else -1) else f (y*x) xs
