import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main
{
  public static void main(String[] args) throws IOException
  {
    BufferedReader r = new BufferedReader(new InputStreamReader(System.in), 1);
    String s;
    String sl[];

    s = r.readLine();
    sl = s.split(" ");

    int n = Integer.parseInt(sl[0]);

    int a[] = new int[101];

    s = r.readLine();
    sl = s.split(" ");
    for(int i = 0; i < n; i++)
    {
    	a[i + 1] = Integer.parseInt(sl[i]);
    }

    int v = 0;
    int c = 0;
    for(int i = 0; i <= n; i++)
    {
        if(c < a[i])
        {
        	v += a[i] - c;
        }
        c = a[i];
    }

    System.out.println(v);
  }

}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz