import java.util.*;

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

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int count = 0;
		int prev = 0;
		for (int i = 0; i < n; i++) {
		    int x = sc.nextInt();
		    if (prev < x) {
		        count += x - prev;
		    }
		    prev = x;
		}
		System.out.println(count);
	}
}
