2crB

#include <iostream>

using std::cin;
using std::cout;
#include "fucn.h"

int main() {
  size_t n, q, k; cin >> n;
  MyString str;
  read(str,n);
  cin >> q;
  char cmd;
  while(q--) {
    cin >> cmd;
    if (cmd == '?') print_size(str);
    else {
      cin >> k;
      if (k--) erase(str, k);
      else cout << pop_back(str) << '\n';
    }
  }
  print(str);
  del(str);
}