fun main(args: Array<String>) {
    if(args.isNotEmpty()) {
        System.setIn(java.io.FileInputStream(args[0]))
    }
 
    fun solve(N: Int, K: Int): String {
        if(K > N) return "(".repeat(N/2) + ")".repeat(N/2)
        if(K == N || K <= 4) return "-1"
        return "(".repeat((N-K-2)/2) + ("(())" + "(".repeat((K-2)/2) + ")".repeat((K-2)/2)) + ")".repeat((N-K-2)/2)
    }
 
    val numTests = readLine()!!.toInt()
    require(numTests in 1..1000)
 
    var sumN = 0
    repeat(numTests) {
        val (N, K) = readLine()!!.split(" ").map{ it.toInt() }
        require(N in 2..100000)
        require(K in 2..100000)
        sumN += N
        require(sumN <= 100000)
        require(N % 2 == 0)
        require(K % 2 == 0)
 
        println(solve(N, K))
    }
 
    require(readLine() == null)
}

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