let input = require('fs').readFileSync('/dev/stdin', 'utf8');
let [N, K, S] = input.split(/\s/);
K = Number(K);
S = S.replace(/\s/, '');
for (let i in S) {
  i = Number(i);
  if (S.match(/\([\s]*\)/)) {
    let M = S.match(/\([\s]*\)/);
    if (M.index == K - 1) {
      console.log(M.index + M[0].length);
      break;
    } else if (M.index + M[0].length == K - 1) {
      console.log(M.index);
      break;
    }
    S = S.replace(/\([\s]*\)/, Array(M[0].length).fill(' ').join ``);
  }
}