import java.util.*;
public class Main {
    public static void main (String [] args) {
        Scanner scn = new Scanner (System.in);
        
        int n = scn.nextInt();
        if (n<0 || n>10) {
            System.out.print("Invalid input");
            return;
        }
        int arr []= new int [n];
        for (int i=0; i<n; i++) {
            if (!scn.hasNextInt()) {
                System.out.print("Invalid input");
                return;
            }
            arr[i]= scn.nextInt();
            if (arr[i]<0 || arr[i]>10000) {
                System.out.print("Invalid input");
                return;
            }
        }
        /*int max=0;
        for (int i=0; i<n-1; i++) {
            if (arr[i]>arr[i+1]){
                max= arr[i];
            }
            else {
                max = arr[i+1];
            }
        }
        System.out.print(max);*/
        
        System.out.print(Math.MAX_VALUE(arr));
    }
}