import java.util.*;

public class Main {
  
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();

    int ans = 0;
    int prevH = 0;
    for (int i = 0; i < N; i++) {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    }
    
    System.out.println(ans);
  }
} import java.util.*; util.* java public class Main {
  
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();

    int ans = 0;
    int prevH = 0;
    for (int i = 0; i < N; i++) {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    }
    
    System.out.println(ans);
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();

    int ans = 0;
    int prevH = 0;
    for (int i = 0; i < N; i++) {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    }
    
    System.out.println(ans);
  } main {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();

    int ans = 0;
    int prevH = 0;
    for (int i = 0; i < N; i++) {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    }
    
    System.out.println(ans);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int ans = 0; ans 0 int prevH = 0; prevH 0 for (int i = 0; i < N; i++) {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    } {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    } int h = sc.nextInt(); h sc.nextInt() sc.nextInt sc if (h >= prevH) {
        ans += h - prevH;
      } h >= prevH h prevH {
        ans += h - prevH;
      } ans += h - prevH ans h - prevH h prevH prevH = h prevH h System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
  
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();

    int ans = 0;
    int prevH = 0;
    for (int i = 0; i < N; i++) {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    }
    
    System.out.println(ans);
  }
} public class Main {
  
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();

    int ans = 0;
    int prevH = 0;
    for (int i = 0; i < N; i++) {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    }
    
    System.out.println(ans);
  }
} Main
import java.util.*;

public class Main {
  
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();

    int ans = 0;
    int prevH = 0;
    for (int i = 0; i < N; i++) {
      int h = sc.nextInt();
      if (h >= prevH) {
        ans += h - prevH;
      }
      prevH = h;
    }
    
    System.out.println(ans);
  }
}