fun anagram(s: String): Int {
    // Write your code here
    if(s.length % 2 !=0)
        return -1
    var res = 0
    val middle = s.length/2
    var sub1 = s.subSequence(0, middle)
    var sub2 = s.subSequence(middle,s.length)
    var s1 = StringBuilder(sub1)
    var s2 = StringBuilder(sub2)
    for(c in s1){
        if(s2.contains(c)){
            val index = s2.indexOf(c)
            s2.deleteCharAt(index)
        }else
            res++
    }
    return res
}