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

public class Main {
	// AtCoder Beginner Contest 116
	// https://atcoder.jp/contests/abc116/tasks
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		int n = sc.nextInt();
		int prevH = 0;
		int res = 0;
		
		for (int i = 0; i < n; i++) {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		}
		System.out.println(res);
		
	}
	
	static class FastReader { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next() { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() { 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
	// AtCoder Beginner Contest 116
	// https://atcoder.jp/contests/abc116/tasks
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		int n = sc.nextInt();
		int prevH = 0;
		int res = 0;
		
		for (int i = 0; i < n; i++) {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		}
		System.out.println(res);
		
	}
	
	static class FastReader { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next() { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() { 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
} Main // AtCoder Beginner Contest 116
	// https://atcoder.jp/contests/abc116/tasks
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		int n = sc.nextInt();
		int prevH = 0;
		int res = 0;
		
		for (int i = 0; i < n; i++) {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		}
		System.out.println(res);
		
	} main {
		FastReader sc = new FastReader();
		int n = sc.nextInt();
		int prevH = 0;
		int res = 0;
		
		for (int i = 0; i < n; i++) {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		}
		System.out.println(res);
		
	} FastReader sc = new FastReader(); sc new FastReader() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int prevH = 0; prevH 0 int res = 0; res 0 for (int i = 0; i < n; i++) {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		} {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		} int height = sc.nextInt(); height sc.nextInt() sc.nextInt sc if (height > prevH) {
				res += (height - prevH);
			} height > prevH height prevH {
				res += (height - prevH);
			} res += (height - prevH) res (height - prevH) height prevH prevH = height prevH height System.out.println(res) System.out.println System.out System System.out res String[] args args static class FastReader { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next() { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() { 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader() { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } FastReader { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } next { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } IOException  e { 
                    e.printStackTrace(); 
                } e.printStackTrace() e.printStackTrace e { 
                    st = new StringTokenizer(br.readLine()); 
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() { 
            return Integer.parseInt(next()); 
        } nextInt { 
            return Integer.parseInt(next()); 
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() { 
            return Long.parseLong(next()); 
        } nextLong { 
            return Long.parseLong(next()); 
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() { 
            return Double.parseDouble(next()); 
        } nextDouble { 
            return Double.parseDouble(next()); 
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() { 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } nextLine { 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } String str = ""; str "" try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } IOException e { 
                e.printStackTrace(); 
            } e.printStackTrace() e.printStackTrace e { 
                str = br.readLine(); 
            } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
	// AtCoder Beginner Contest 116
	// https://atcoder.jp/contests/abc116/tasks
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		int n = sc.nextInt();
		int prevH = 0;
		int res = 0;
		
		for (int i = 0; i < n; i++) {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		}
		System.out.println(res);
		
	}
	
	static class FastReader { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next() { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() { 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
} public class Main {
	// AtCoder Beginner Contest 116
	// https://atcoder.jp/contests/abc116/tasks
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		int n = sc.nextInt();
		int prevH = 0;
		int res = 0;
		
		for (int i = 0; i < n; i++) {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		}
		System.out.println(res);
		
	}
	
	static class FastReader { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next() { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() { 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	// AtCoder Beginner Contest 116
	// https://atcoder.jp/contests/abc116/tasks
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		int n = sc.nextInt();
		int prevH = 0;
		int res = 0;
		
		for (int i = 0; i < n; i++) {
			int height = sc.nextInt();
			
			if (height > prevH) {
				res += (height - prevH);
			}
			prevH = height;
		}
		System.out.println(res);
		
	}
	
	static class FastReader { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() { 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
  
        String next() { 
            while (st == null || !st.hasMoreElements()) { 
                try { 
                    st = new StringTokenizer(br.readLine()); 
                } catch (IOException  e) { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() { 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
}
