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); } }