#include <iostream>
#include <string>
#include <cctype>
#include <map>

using namespace std;

string s;
int i;
map<int, int> s_cache, r_cache;

int rec(int s_begin, int r_offset, int &s_length, int &r_length, bool includes)
{
  map<int, int>::iterator p;

  if (includes || ((p = s_cache.find(s_begin)) == s_cache.end())) {
    int si = 0, ri = 0;
    while (true) {
      if (s[s_begin + si] == '$') { break; }
      if (s[s_begin + si] == ')') { si++; break; }
      if (isalpha(s[s_begin + si])) {
        if (r_offset + ri == i) { return s[s_begin + si]; } si++; ri++;
      }
      if (isdigit(s[s_begin + si])) {
        int digit = 0;
        while (s[s_begin + si] != '(' && !isalpha(s[s_begin + si])) {
          digit *= 10;
          digit += s[s_begin + si] - '0';
          si++;
        }
        if (s[s_begin + si] == '(') {
          si++;
          int s_length_;
          for (int j = 0; j < digit; j++) {
            int r_length_, found;
            found = rec(s_begin + si, r_offset + ri, s_length_, r_length_, false);
            if (found) { return found; }
            ri += r_length_;
          }
          si += s_length_;
        } else if (isalpha(s[s_begin + si])) {
          if (r_offset + ri <= i && i < r_offset + ri + digit) { return s[s_begin + si]; }
          ri += digit;
          si++;
        }
      }
    }
    s_length = si;
    r_length = ri;
    s_cache.insert(make_pair(s_begin, s_length));
    r_cache.insert(make_pair(s_begin, r_length));
  } else {
    s_length = p->second;
    map<int, int>::iterator q = r_cache.find(s_begin);
    r_length = q->second;
    if (r_offset <= i && i < r_offset + r_length) {
      int found;
      found = rec(s_begin, r_offset, s_length, r_length, true);
      if (found) { return found; }
    }
  }
  return 0;
}

int main()
{
  while (true) {
    cin >> s >> i; if (s == "0" && i == 0) { break; }

    int s_length, r_length;
    s_cache.clear();
    r_cache.clear();
    s += "$";
    int found;
    found = rec(0, 0, s_length, r_length, true);
    if (found) { cout << ((char)found) << endl; }
    else { cout << 0 << endl; }
  }
  return 0;
}