import Foundation

let n = Int(readLine()!)!
let str = readLine()!

let words = str.components(separatedBy: " ")
var ans: UInt64 = 1
let max: UInt64 = 1000000000000000000
for i in 0..<n {
    let num = UInt64(words[i])!
    ans *= num
    if ans > max {
        //print("\(ans) : \(max)")
        print("-1")
        exit(0)
    }
}

print("\(ans)")

