

// 값 입력받는 코드
const readline = require('readline');
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
});
let input = [];
rl.on('line', function (line) {
input.push(line);
}).on('close', function (){
solution(input);
process.exit();
});
// 풀이코드
function solution(input){
input2 = input[0].split('');
let answer=0;
let stack = [];
for (let i = 0; i < input2.length; i++) {
if (input2[i] === '(') {
if (input2[i + 1] === ')') {
answer+=stack.length;
i+=1;
} else {
stack.push('(');
}
}
else{
stack.pop();
answer+=1;
}
}
console.log(answer);
}