#include <bits/stdc++.h>
using namespace std;
string onezero(int n) {
  string s = "1";
  for (int i = 1; i < n; ++i) {
    s += "0";
  }
  return s;
}
string findSum(string str1, string str2) {
  if (str1.length() > str2.length()) swap(str1, str2);
  string str = "";
  int n1 = str1.length(), n2 = str2.length();
  reverse(str1.begin(), str1.end());
  reverse(str2.begin(), str2.end());
  int carry = 0;
  for (int i = 0; i < n1; i++) {
    int sum = ((str1[i] - '0') + (str2[i] - '0') + carry);
    str.push_back(sum % 10 + '0');
    carry = sum / 10;
  }
  for (int i = n1; i < n2; i++) {
    int sum = ((str2[i] - '0') + carry);
    str.push_back(sum % 10 + '0');
    carry = sum / 10;
  }
  if (carry) str.push_back(carry + '0');
  reverse(str.begin(), str.end());
  return str;
}
int main() {
  ios_base::sync_with_stdio(NULL);
  cin.tie(NULL);
  cout.tie(NULL);
  int l;
  string s, ans;
  cin >> l >> s;
  if (s.size() % l != 0) {
    string zero = onezero(l);
    for (int i = 0; i < s.size() / l + 1; ++i) {
      ans += zero;
    }
  } else {
    string temp = s.substr(0, l);
    for (int i = 0; i < s.size() / l; ++i) {
      ans += temp;
    }
    if (ans <= s) {
      ans = "";
      temp = findSum(temp, "1");
      if (temp.size() != l) {
        temp = onezero(l);
        ans = onezero(l);
      }
      for (int i = 0; i < s.size() / l; ++i) {
        ans += temp;
      }
    }
  }
  cout << ans << endl;
}
