import java.util.Scanner;

public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int n;
		n = sc.nextInt();
		int[]  h = new int [n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}

		int ans = 0;
		int out = 0;

		for( int i = 0; i < h.length; i++ ) {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		}

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

		int ans = 0;
		int out = 0;

		for( int i = 0; i < h.length; i++ ) {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		}

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

		int ans = 0;
		int out = 0;

		for( int i = 0; i < h.length; i++ ) {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		}

		System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		int n;
		n = sc.nextInt();
		int[]  h = new int [n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}

		int ans = 0;
		int out = 0;

		for( int i = 0; i < h.length; i++ ) {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		}

		System.out.println(ans);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n; n n = sc.nextInt() n sc.nextInt() sc.nextInt sc int[]  h = new int [n]; h new int [n] n for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			h[i] = sc.nextInt();
		} {
			h[i] = sc.nextInt();
		} h[i] = sc.nextInt() h[i] h i sc.nextInt() sc.nextInt sc int ans = 0; ans 0 int out = 0; out 0 for( int i = 0; i < h.length; i++ ) {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		} int i = 0; int i = 0; i 0 i < h.length i h.length h h.length i++ i++ i {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		} {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		} if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			} out < h[i] out h[i] h i {
				ans += h[i] - out;
				out =  h[i];
			} ans += h[i] - out ans h[i] - out h[i] h i out out =  h[i] out h[i] h i {
				out = h[i];
			} out = h[i] out h[i] h i 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;
		n = sc.nextInt();
		int[]  h = new int [n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}

		int ans = 0;
		int out = 0;

		for( int i = 0; i < h.length; i++ ) {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		}

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

		int ans = 0;
		int out = 0;

		for( int i = 0; i < h.length; i++ ) {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		}

		System.out.println(ans);
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int n;
		n = sc.nextInt();
		int[]  h = new int [n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}

		int ans = 0;
		int out = 0;

		for( int i = 0; i < h.length; i++ ) {
			if( out < h[i] ) {
				ans += h[i] - out;
				out =  h[i];
			}else {
				out = h[i];
			}
		}

		System.out.println(ans);
	}
}