import java.util.Stack
 
fun main() {
    val br = System.`in`.bufferedReader()
    val stack = Stack<Char>()
 
    val str = br.readLine()
    var prevOpen = false
    var count = 0
    for (c in str) {
        when (c) {
            '(' -> {
                prevOpen = true
                stack.push(c)
            }
            ')' -> {
                if (prevOpen) {
                    stack.pop()
                    count += stack.size
                } else {
                    stack.pop()
                }
                prevOpen = false
            }
        }
    }
 
    println(count)
}

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