B. Sum of Digits

import java.util.Scanner;

public class Solution {


    public static void main(String[] args) {


        Scanner scan = new Scanner(System.in);

        int n = scan.nextInt();
        int[] arr = new int[n];

        for (int i = 0; i < arr.length; i++) {
            arr[i] = scan.nextInt();

        }

        int e = 0;
        int d = 0;
        int c = 0;

        for (int i = 0; i < arr.length; i++) {

            if ((c + e) < arr[i]) {
                d += arr[i] - (c + e);
            }

            if(c > arr[i]){
                e += c - arr[i];
            }else if(c < arr[i]){
                e -= arr[i] - c;
                if(e < 0) e = 0;
            }


            c = arr[i];
        }

        System.out.println(d);
    }

}