_ = Int(readLine()!)!
var numbers = readLine()!.split(separator: " ").map({ Int($0)! })
if numbers.contains(0) {
    print(0)
} else {
	let result = numbers.reduce(1) { $0 * $1 }
	let limit = { () -> Int in
    	var j = 1
    	for _ in 0..<19 {
        	j *= 10
	    }
    	return j
	}()
  
	print((result >  limit) ? -1 : result )
}