#include <iostream>
using namespace std;

int main() {
  int n;
  cin >> n;
  int maxNum1 = -1;
  int maxNum2 = -1;
  int maxSum = -1;
  int x;

  for (int i = 0; i < n; i++) {
    cin >> x;

    if(x > maxNum1) {
      maxNum1 = x;
    }
    else {
      if((x + maxNum1) % 1009 == 30 && x + maxNum1 > maxSum) {
        maxSum = x + maxNum1;
        maxNum2 = x;
      }
    }
  }

  cout << maxNum1  << maxNum2 << endl;

  return 0;
}