#include <stdio.h>

int main(void)
{
  short n, k, i, flug = -1;
  scanf("%hd%hd", &n, &k);
  char s[n];
  scanf("%s", s);

  for(i = 0;; i++){
    if(i == n){
      i = 0;
      flug = -1;
    }
    if(s[i] == '(')
      flug = i;
    else if(s[i] == ')'){
      if(flug != -1){
        if(k - 1 == flug){
          printf("%hd\n", i + 1);
          return 0;
        }
        else if(k - 1 == i){
          printf("%hd\n", flug + 1);
          return 0;
        }
        s[flug] = 0;
        s[i] = 0;
      }
      flug = -1;
    }
  }
}