import java.util.*;
import java.lang.*;

public class N597 {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int t = sc.nextInt();
    int[] x = new int[t];
    StringBuffer sb = new StringBuffer();
    for(int i = 1; i < t; i++) {
      sb.append(sc.nextInt(i));
    }
    System.out.println(sb);
  }
}