import java.util.*;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] h = new int[n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}
		int answer = 0;
		for(int i = 0; i < n; i++) {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		}
		System.out.println(answer);
	}

} 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[] h = new int[n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}
		int answer = 0;
		for(int i = 0; i < n; i++) {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		}
		System.out.println(answer);
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] h = new int[n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}
		int answer = 0;
		for(int i = 0; i < n; i++) {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		}
		System.out.println(answer);
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] h = new int[n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}
		int answer = 0;
		for(int i = 0; i < n; i++) {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		}
		System.out.println(answer);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int 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 answer = 0; answer 0 for(int i = 0; i < n; i++) {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		} {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		} while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			} h[i] != 0 h[i] h i 0 {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			} answer += 1 answer 1 for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				} int j = i; int j = i; j i j < n j n j++ j++ j {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				} {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				} if(h[j] <= 0)
						break;
					else
						h[j] -= 1; h[j] <= 0 h[j] h j 0 break; h[j] -= 1 h[j] h j 1 System.out.println(answer) System.out.println System.out System System.out answer String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] h = new int[n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}
		int answer = 0;
		for(int i = 0; i < n; i++) {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		}
		System.out.println(answer);
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] h = new int[n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}
		int answer = 0;
		for(int i = 0; i < n; i++) {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		}
		System.out.println(answer);
	}

} Main
import java.util.*;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] h = new int[n];
		for(int i = 0; i < n; i++) {
			h[i] = sc.nextInt();
		}
		int answer = 0;
		for(int i = 0; i < n; i++) {
			while(h[i] != 0) {
				answer += 1;
				for(int j = i; j < n; j++) {
					if(h[j] <= 0)
						break;
					else
						h[j] -= 1;
				}
			}
		}
		System.out.println(answer);
	}

}